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Bureau of Mines Information Circular/1987 



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Human Engineering and Human 
Resources Management in Mining 

Proceedings: Bureau of Mines Technology 
Transfer Seminar, Pittsburgh, PA, July 7-8, 
1987; St. Louis, MO, July 15-16, 1987; and San 
Francisco, CA, July 21-22, 1987 

Compiled by Staff, Bureau of Mines 



rtyi 




UNITED STATES DEPARTMENT OF THE INTERIOR 




Information Circular 9145 

it 



Human Engineering and Human 
Resources Management in Mining 

Proceedings: Bureau of Mines Technology 
Transfer Seminar, Pittsburgh, PA, July 7-8, 
1987; St. Louis, MO, July 15-16, 1987; and San 
Francisco, CA, July 21-22, 1987 

Compiled by Staff, Bureau of Mines 



UNITED STATES DEPARTMENT OF THE INTERIOR 
Donald Paul Hodel, Secretary 

BUREAU OF MINES 

David S. Brown, Acting Director 



■Uif 



Library of Congress Cataloging-in-Publication Data: 



Bureau of Mines Technology Transfer Seminars (1987: Pittsburgh, PA, 
St. Louis, MO, and San Francisco, CA) 

Human engineering and human resources in mining 



(Information circular/United States Department of the Interior, Bureau of Mines; 9145) 

Includes bibliographies. 

1. Human engineering— Congresses. 2. Mine safety— Congresses. I. United States. Bureau of 
Mines. II. Title. III. Series: Information Circular (United States. Bureau of Mines); 9145. 



TN295.U.4 [HD7269.M6] 622s [622 '.8] 



87-600198 



PREFACE 

This Information Circular summarizes recent efforts by the Bureau of Mines to reduce ac- 
cidents and improve performance in both surface and underground mines through research on the 
human factors-ergonomics aspects of mining. The 18 papers contained in this publication were 
presented at a 2-day Bureau of Mines technology transfer seminar on human engineering and human 
resources in mining during July 1987 at three locations. The work presented represents only a small 
portion of the research currently being conducted by the Bureau to improve the health and safety 
of mine workers and to boost mine productivity through the development of more effective, effi- 
cient mining technology. 

Information about other research programs or about technology transfer activities sponsored 
by the Bureau to introduce completed research to potential users, may be obtained by writing the 
Bureau of Mines, Branch of Technology Transfer, 2401 E. Street NW, Washington, DC 20241. 



Ill 



CONTENTS 

Page 

Preface i 

Abstract 1 

Introduction 1 

Analysis of Selected Back Injuries Occurring in Underground Coal Mining, by Thomas G. Bobick, 

Terry J. Stobbe, and Ralph W. Plummer 2 

Analyses of Materials-Handling Systems in Underground Low-Coal Mines, by Thomas G. Bobick 13 

Back Strength and Lifting Capacity of Underground Miners, by Sean Gallagher 21 

Ergonomic Analysis of the Jackleg Drill, by Thomas G. Bobick, William Marras, and Steven A. Lavender ... 33 
Computer-Aided Analysis of Human Factors Aspects of Mining Crewstations, by Richard L. Unger and 

James P. Rider 44 

Maintainability Design of Mobile Underground Mining Equipment, by Ernest J. Conway and 

Richard L. Unger 61 

Assessment of Illumination for Tasks Performed by Operators of Mobile Surface Coal Mining Equipment, 

by Alan G. Mayton 66 

Analysis of Maintenance and Repair Accidents on Haulage Trucks, by Thomas J. Albin and 

Dennis A. Long 75 

Determining Effects of Management Practices on Coal Miners' Safety, by Gregory Gaertner, Paul Newman, 

Shelley Perry, Gerald P. Fisher, and Kenneth C. Whitehead 82 

Miners' Absenteeism: Consequences, Causes, and Control, by Robert H. Peters 95 

Examination of the Design of Bonus Plans in Underground Mining, by Paul S. Goodman 106 

Basic Guidelines for Establishing an Employee Assistance Program, by N. D. Campbell 117 

Employee Assistance Programs, Benefits of Services, and Activities of the Mining Industry Substance Abuse 

Committee, by Frank C. Fantauzzo and Suzanne Smith 123 

Facilitating Supervisory Performance: A Workshop Approach, by Ronald Althouse and James M. Peay 128 

The Hecla Story: Organization Development in the Hard-Rock Mining Industry, by Cecil H. Bell, Jr 138 

Structured Management Training in Underground Mining— Five Years Later, by Fred E. Fiedler 149 

Management Considerations in Reducing the Alertness Problem Among Mine Equipment Operators, by 

Jon A. Wagner 154 

Simple Computerized Decision-Support System for Managing Coal Mine Productivity, by R. F. Randolph .... 165 





UNIT OF MEASURE ABBREVIATIONS USED IN THIS REPORT 


deg 


degree 


L/min 


liter per minute 


deg/s 


degree per second 


min 


minute 


op 


degree Fahrenheit 


mL 


milliliter 


fc 


footcandle 


(mL/kg)/min 


milliliter per kilogram 


fL 


footlambert 




per minute 


ft 


foot 


mV 


microvolt 


ft.lb 


foot pound 


pet 


percent 


gal 


gallon 


s 


second 


h 


hour 


St 


short ton 


in 


inch 


st/d 


short ton per day 


kcal 


kilocalorie 


st/h 


short ton per hour 


kcal/min 


kilocalorie per minute 


V 


volt 


lb 


pound 


yr 


year 



HUMAN ENGINEERING AND HUMAN RESOURCES MANAGEMENT 

IN MINING 

Proceedings: Bureau of Mines Technology Transfer Seminar, 

Pittsburgh, PA, July 7-8, 1987; St. Louis, MO, July 15-16, 

1987; and San Francisco, CA, July 21-22, 1987 

Compiled by Staff, Bureau of Mines 



ABSTRACT 

The Bureau of Mines human factors research program is directed toward reducing 
accidents and improving the overall efficiency of the person-machine environment in- 
terface found in surface and underground mines. The focus of the human factors pro- 
gram therefore, is to insure that sound knowledge is available concerning human 
capabilities and limitations, and that this knowledge is applied to the design of mining 
equipment, work tasks, and management procedures. 

The papers presented in these proceedings summarize some of the recent Bureau 
research in human factors. The papers focus on two broad areas, human resource issues 
and human engineering of equipment, tools, and work procedures found in mines. 



INTRODUCTION 



For more than 75 yr the Bureau has been engaged in 
efforts to reduce mining fatalities and injuries. The success 
of these endeavors can be readily grasped by observing the 
almost uninterrupted decline in mining injuries over this 
extended period. In the early part of the 20th century, 2,000 
or more mining fatalities occurred annually; the greater por- 
tion of these were due to mine explosions and fires. In 1986, 
124 fatalities were reported and none were due to 
catastrophic explosions and fires. 

Mine disasters, while now relatively rare, still capture 
the public's attention, and by any standard are tragedies 
deserving of every effort to prevent their recurrence. 
However, the fact remains that today most mining accidents 
that result in death or injury are single occurrences and 
are often associated with human performance factors. 
Williard Stanley, Kentucky Commissioner of Mines and 
Minerals, writing in The Scoop, v. 1, No. 11, said: 

"The basic principles of . . . mining in relation to the 
environment have been the same for many years and 
we have learned to a great extent how to make 
a . . . mine a safer place to work. Now we must con- 
trol the human element. Since what we do or fail to 
do causes 90% of all accidents . . . ." 

Even though this percentage estimate might be debated, 
most knowledgeable mining officials agree that human per- 
formance is a significant factor in mining accidents. Too 



often, though, inadequate or inappropriate performance is 
attributed to individual volition and dismissed as human 
error. This circumstance gives the appearance of providing 
an explanation for causes of human behavior without 
really doing so. When individuals commit errors there are 
natural causes for these mistakes, and the appropriate 
course of action is to seek to discover these causes and in- 
stitute countermeasures based on sound scientific informa- 
tion. For example, operator compartments on some pieces 
of equipment are so designed that operator errors and in- 
juries are probable. Also, management practices in some 
companies may, at times, provide insufficient motivation 
for a safe and effective workforce, and may even be in- 
advertently perceived by individuals as encouraging risk 
taking. 

The Bureau's human factors research program is 
directed toward researching the causes of accidents, injuries, 
and productivity problems that are related to the human 
element. The following 18 papers summarize some of the 
recent Bureau research in this area. The papers cover a 
broad area and are intended not only to provide the min- 
ing community with useful data for immediate application 
to mining situations but also to stimulate fresh thinking 
on new ways to approach very old problems. The papers 
focus on two broad areas, human resource issues, or topics 
related generally to management practices; and human 
engineering of equipment, tools, and work procedures found 
in mines. 



AN ANALYSIS OF SELECTED BACK INJURIES OCCURRING IN 
UNDERGROUND COAL MINING 



By Thomas G. Bobick, 1 Terry J. Stobbe, 2 and Ralph W. Plummer 3 



ABSTRACT 

Musculoskeletal injuries are a constant problem in the underground coal mining 
industry. Back injuries represent the largest single category of lost-time injuries. Tradi- 
tional attempts to address the problems consist of compiling statistics from standard 
accident report forms to identify the jobs and activities that caused the back injuries. 
This research project, which is sponsored by the Bureau of Mines and conducted by West 
Virginia University (WVU), is conducting back-injury investigations that are more com- 
prehensive than the traditional methods. Arrangements have been made with six coal 
mining companies in four States to call WVU when a back injury occurs. A thorough 
investigation is conducted by WVU personnel within a few weeks to document the en- 
vironmental, biomechanical, behavioral, and task-related variables associated with the 
injury. Interviews with supervisory and safety department personnel are also part of 
the investigation. Results from 100 accident investigations are presented. 



INTRODUCTION 



SCOPE OF THE PROBLEM 

Underground mining involves a great deal of manual 
handling of parts, supplies, and equipment. As the amount 
of manual handling increases, the potential for a lost-time 
injury also increases. These injuries usually involve the 
musculoskeletal system of the worker. Musculoskeletal 
disorders are a leading cause of work-related injuries in the 
mining industry. These types of injuries are usually 
classified as sprains and strains. In 1983 and 1984, sprains 
and strains represented 24 and 25 pet, respectively, of all 
lost-time injuries in the underground coal industry (I). 4 The 
corresponding 1983-84 average days lost per lost-time sprain 
and strain injury were 19.0 and 21.5. 

The most serious type of sprain and strain injury in- 
volves the lower back. In 1983 and 1984, accident statistics 
indicate that injuries to the back represented 55 and 54 pet 
of all lost-time sprain and strain injuries. Injuries to the 
knees, which represented about 11 pet for each year, was 
the second most common body part injury in underground 
coal mining. 

Considering severity, knee injuries have a higher 
number of lost days associated with them than back injuries 
(29.1 versus 19.3 days), but the total number of lost 



1 Mining engineer, Bureau of Mines, Pittsburgh Research Center, Pitts- 
burgh, PA. 

2 Associate professor, Department of Industrial Engineering, West Vir- 
ginia University, Morgantown, WV. 

3 Professor, Department of Industrial Engineering, West Virginia Uni- 
versity, Morgantown, WV. 

4 Italic numbers in parentheses refer to items in the list of references 
preceding the appendix at the end of this paper. 



workdays for all back injuries greatly exceeds the total 
number of lost days for all knee injuries by a factor of 
greater than 3 (26,500 versus 8,600). Although knee injuries 
are more severe than back injuries (6 work weeks off ver- 
sus 4 work weeks) there were almost five times the number 
of lost-time back injuries (1,450 versus 300). Thus, when 
considering the total impact on the industry, the com- 
munity, and the families, worker back injuries represent 
a ubiquitous problem for all sectors of underground coal 
mining. 

OVERVIEW OF THE PROJECT 

In an effort to assist in controlling the ever-growing back 
injury problem, the Bureau initiated a multifaceted ap- 
proach. This included starting a comprehensive in-house 
effort to research a variety of factors relating to low back 
pain of underground coal miners. Various aspects of the in- 
house work are discussed in two other papers in this Infor- 
mation Circular. 

In addition to the in-house research program, the 
Bureau funded an effort to conduct a thorough investiga- 
tion of accidents that involve a back injury at mining com- 
panies that agreed to cooperate with the research. Non-lost- 
time incidents were also investigated. 

The scope of the research contract 5 is to determine if 
a relationship can be identified among the workers, the 
materials handled, the tasks that have to be conducted, and 
the environmental conditions, with respect to the occurrence 
of back injuries in the underground coal mining industry. 



5 J0348044, "Research Study of Back Injuries in Underground Coal Min- 
ing," West Virginia University. 



METHOD OF DATA COLLECTION 



BACKGROUND 

Analogous to infectious diseases, occupational low-back 
injuries can be treated once they occur, but the concept of 
immunization (i.e., preventing them from occurring initial- 
ly) is more important. The science of epidemiology is de- 
fined as the study of the distribution and determinants of 
diseases and injuries in human populations (2). 

Epidemiology is used to identify common characteristics 
and factors, which initially may be seemingly unrelated, 
that may have statistically significant effects related to the 
occurrence of diseases, including occupational injuries. 
Early work in this field included classic studies related to 
the occurrence of scurvy in sailors, and smallpox and cholera 
epidemics (3). Presently, epidemiology is the cornerstone 
of studies that have helped to identify the risk factors 
related to stroke (the Framingham study) and, of course, 
the finding of the cause of Legionnaire's disease. In the 
previous examples, a specific agent caused the affliction, 
such as the lack of citrus fruit in the diet, the highly infec- 
tious pox virus, or the polluted drinking water. 

Similarly (4), "the primary agent causing [occupational] 
injuries is energy. Control efforts are aimed at reducing its 
release to the body in dangerous amounts." This concept 
of an overdose of energy applied to the musculoskeletal 
system is quite appropriate for the mining industry, and 
will be shown to be frequently involved in causing lost-time 
injuries. 

PRESENT PROJECT 



The objective of this project is to investigate, in detail, 
a total of 200 back injuries as they occur in the underground 
coal mining industry. At the time of preparing this paper, 
110 accidents had been investigated. The data presented 
in this paper, however, will be limited to 100 injuries. 

This project is being conducted with 11 cooperating 
mines that are located in four States (West Virginia, Penn- 
sylvania, Illinois, and Kentucky) and owned by six com- 
panies. The majority of the mines use electric equipment, 
but a few of the mines do utilize diesel-powered equipment. 



Average seam thickness varies from less than 5 ft to more 
than 8 ft. Average mine employment varies from under 100 
to over 600. Mining methods represented include longwall 
and room and pillar. No operations employing conventional 
mining techniques are represented in the study. 

The intent of this project is to collect information related 
to back injuries in more detail than typically acquired in 
the usual review and tabulation of accident and injury 
statistics. Basically, the data collection consists of review- 
ing the accident reports and then conducting a detailed in- 
terview with the injured worker(s), their immediate super- 
visors), and a representative of the mine's safety depart- 
ment within 1 to 3 weeks of the accident. The interview is 
structured along a format designed to determine specific 
facts about the following areas: 

1. Job- or task-related variables (posture, movement, 
occurrence, weight lifted, estimate of force exerted, load size, 
surface conditions, etc.). 

2. Personnel-related variables (height, weight, body mor- 
phology, medical-incident history, work history, training 
and experience, injury data, treatment data, etc.). 

3. Production-related variables (reason for doing task that 
way, alternative methods, does a standard operating pro- 
cedure (SOP) exist and was it followed, if not why not, etc.). 

4. Other variables not fitting into preceding areas 
(unique environmental conditions, unique hazards, in- 
dustrial engineering (IE) methods analysis, etc.). 

The interviews, which take about an hour to complete, 
are conducted before, during, or after the work shift, depend- 
ing on the miner's availability. A copy of the interview form 
is presented in the appendix to this paper. Many of the com- 
panies have incorporated some of the more pertinent items 
into their usual accident investigation form. 

There were some fears on the part of both union and 
management that injured miners would be unwilling to 
discuss their injuries with the researchers, but in fact they 
have been very cooperative, often going into much more 
detail than originally requested. At the end of the project, 
the data collected on these variables will be analyzed 
using appropriate statistical methods to determine which 
factors or which combination of factors may be highly cor- 
related to the incidence of back injures. 



RESULTS 



As mentioned, the results of this research are based on 
100 accident investigations; these were divided almost 
equally between lost-time and non-lost-time injuries. The 
following tables were prepared to provide an overview of 
the results being collected in this project. The first five 
tables are summary tables similar to those found in most 
typical injury reports. The sixth table presents specific 
aspects of one of the more interesting early findings of the 
research— the importance of sudden movement in the 
etiology of musculoskeletal injuries. The seventh table pro- 
vides a more complicated analysis of selected data. 

Table 1 presents data on the frequency of back injuries 
with respect to job classification, broken down according to 
lost-time and non-lost-time injuries. Of the miners inter- 
viewed, those with the job classification of general laborer 
suffered 22 pet of the back injuires, which made general 
laborer the highest incident category. Maintenance 



mechanics had 17 pet of the back injuries, while roof bolter 
operators were third with 16 pet. The next two job classifica- 
tions, in terms of frequency of back injuries, were the 

Table 1.— Comparison of frequency of injuries for coal 
mining jobs, percent 

Job title LT NLT Total 

General laborer 13 9 22 

Maintenance mechanic 4 13 17 

Roof bolter operator 11 5 16 

Continuous miner operator 4 5 9 

Shuttle car operator 4 3 7 

Supervisor 2 5 7 

Conveyor belt worker 3 1 4 

Electrician 3 3 

Surveyor-rod worker 2 2 

Longwall helper 2 2 

Other _5 _6_ 11 

Totals 49 51 100 

LT Lost-time injury. NLT Non-lost-time injury. 



operators of the continuous miner and shuttle car with 9 
and 7 pet, respectively. The percentage of shuttle car 
operator injuries agrees exactly with a previous analysis 
conducted on 1981 injury statistics. (5). 

Table 2 contains information regarding the reason the 
task was being performed. The most frequent reason (17 
pet of the cases) was routine maintenance. Other frequent 
reasons for performing the tasks were routine roof bolting 
( 10 pet), bad top (9 pet), routine haulage and routine equip- 
ment moves (8 pet each). Of the miners suffering back in- 
juries, virtually all of them were performing tasks that they 
described as a normal part of their job duties. 



Table 2.— Frequency of reason for task being performed 
when injury occurred, percent 

Reason 

Routine maintenance 17 

Routine roof bolting 10 

Bad top 9 

Routine haulage 8 

Routine equipment moves 8 

Routine housekeeping 6 

Prevent roof and rib deterioration 5 

Equipment failure 5 

Resupply section 5 

Moving ventilation curtain 3 

Longwall move 3 

Belt-line maintenance 2 

Nonroutine maintenance (track) 1 

Other 18 

Total 100 



In table 3, the activity at the time of the injury has been 
coded into the categories that are used in the Mine Safety 
and Health Administration (MSHA) reporting system. As 
expected, a variety of activities have caused the back in- 
juries. Materials handling is by far the most frequent ac- 
tivity at the time of injury (38 pet). This agrees quite closely 
with previous analyses (1 , 6) that indicated materials han- 
dling was involved with 34 pet, 38 pet, and 35 pet of the 
lost-time accidents in underground coal mining in 1980, 
1983, and 1984, respectively. Injuries due to timbering (8 
pet) and handling roof bolts or drill steels (7 pet) account 
for two-fifths of the materials-handling injuries. Handling 
cables is the next most hazardous activity, with 16 pet of 
the injuries. Conducting equipment maintenance was the 
third most hazardous activity, the source of 14 pet of the 
back injuries investigated. 

Table 3.— Frequency of activity at the time of injury, 
according to MSHA coding system, percent 

Activity 

Materials handling 38 

Cable handling 16 

Equipment maintenance 14 

Operating shuttle car 7 

Roof bolting (n.e.c.) 4 

Shoveling 4 

Barring down rib or top 3 

Walking in mine 3 

Operating continuous miner 3 

Entering or exiting equipment 2 

Other _6 

Total 100 

n.e.c. Not elsewhere classified. 

The following are specific activities identified for 74 of 
the first 100 back injuries investigated. The most striking 
aspect of this list is the tremendous range of events that 
provoked a back injury. The data in table 3 and the follow- 
ing list reflect the inherent shortcoming in any injury data 



classifying scheme— a significant loss of pertinent informa- 
tion about the situation that produced the injuries. 



Climbing off a machine. 

Dragging wet ventilation curtain. 

Walking backwards with hose, tripped. 

Moving continuous miner cable and water line. 

Building cribbing. 

Restocking roof bolter. 

Rolling 4-ft spool of miner cable. 

Resetting cable and water line. 

Teletram hit continuous miner. 

Drilling hole with roof bolter, slate fell. 

Shuttle car steering failed, hit rib. 

Reaching over machine side, lifting motor cover. 

Using pry bar to hold bracket. 

Lifting 4- by 8-in by 18-ft header. 

Driving shuttle car. 

Shoveling coal and slate. 

Dragging hose. 

Reaching for 5-ft length of polyvinylchloride (PVC) 

pipe. 

Walking downhill. 

Bending roof bolt in a hole. 

Repairing teletram differential. 

Shuttle car hit feeder-conveyor. 

Prying on gathering head motor. 

Driving shuttle car, hit bad bump. 

Removing drill steel. 

Hammering surveying spads in low coal, awkward 

posture. 

Turning over box of six self-contained self-rescuers. 

Pushing dust box out of scoop bucket. 

Picking up two rock-dust bags. 

Walking, stepped in hole. 

Cutting bottom with continuous miner, large jolt. 

Picking up fallen top when a new piece fell. 

Lifting oxygen cylinder. 

Lifting 5-gal bucket of bits. 

Lifting and pulling timbers through mandoor. 

Transferring toolbox. 

Handling 6-in by 16-ft I-beams. 

Reloading roof bolter with rock-dust bags. 

Lifting 7,200-V power cable. 

Bending over and standing up. 

Prying 150-lb plate out of box. 

Walking across a supply car. 

Moving crib blocks. 

Standing on roof bolter drill head to use a torque 

wrench. 

Lifting a steel bar. 

Rock fell while roof bolting. 

Carrying transit and tripod. 

Exiting from mantrip. 

Inserting roof bolt into hole. 

Pushing a wheelbarrow. 

Pulling a box out of the elevator. 

Picking up a bag of oil dry. 

Loading a toolbox into scoop bucket. 

Pushing rock duster into scoop bucket. 

Lifting sheave to move hydraulic cylinder. 

Helping others to move a railstop welded to large 

plate. 

Lifting panel cover of scoop. 

Tossing small box into elevator, twisted trunk. 

Carrying a gear in an awkward posture. 



Lifting wooden rail tie. 

Standing on roof bolter drill head to reach high 

roof. 

Using pry bar to move a longwall hydraulic jack. 

Removing slate from the top with pry bar. 

Carrying 5 gal of water (greater than 40 lb). 

Standing on roof bolter in high top area, fell off. 

Inspecting roof and rib. 

Taking down ventilation curtain. 

Changing scoop tire (300 lb). 

Carrying mandoor. 

Carrying rock-dust bag, stepped in hole. 

Repairing roof bolter, motor fell, pulled worker 

forward. 

Carrying two 5-gal cans of oil. 

Backing the continuous miner, hit hole, bad jolt. 

Disconnecting railcars. 



Table 4 presents the agent associated with the injury, 
as coded in the MSHA system. The table indicates that no 
one item is dominant in the cause of back injuries. Using 
the MSHA coding system, 26 separate categories contained 
at least one entry. Thus, the other category represents 17 
other items that caused a back injury. The data presented 
in tables 3 and 4 and the listing strongly suggest that the 
underlying mechanism in back injuries is extremely diverse 
in its nature. 

Table 4.— Distribution of agents associated with 
back injuries, percent 

Agent 

Electric conductors 16 

Underground mining machine 11 

Rock, coal, ore 11 

Bodily motion 9 

Boxes, crates, cartons 9 

Drill steel, roof bolts 6 

Posts, cribs, ties, timbers 5 

Bags 5 

Mine floor, working surface 4 

Other _24 

Total 100 



stood on the bolter machine to insert the roof bolt. When 
the task was completed, the operator stepped off the bolter 
into loose rock and slipped, sustaining a back injury. 
Another example of a nonroutine task involved a miner be- 
ing injured while helping five others to lift and move a 
railcar stop so track maintenance could be accomplished. 
The carstop was welded to a 3/4-in-thick piece of steel that 
measured 3 by 4 ft and weighed over 350 lb. Basically, 
however, nonroutine tasks were uncommon events and were 
responsible for only 8 pet of the back injuries. 

One of the more interesting findings of this research so 
far is the importance of sudden movement as a factor in back 
injuries. The typical scenario is one in which either the per- 
son or the load shifts suddenly and unexpectedly. This can 
happen while riding in a vehicle that hits a bump or col- 
lides with another vehicle, or when walking through the 
mine and a worker slips but does not fall, or while carry- 
ing a load that shifts suddenly. In each case, the loading 
on the neuromuscular system occurs in a matter of mil- 
liseconds, and either of two events results. 

First, the system cannot respond with the appropriate 
muscular contractions to provide protection for the body 
(when riding); second, in the case of the nonfalling slip, the 
body's natural reaction to prevent the fall causes the trunk 
muscles to overrespond and thus overload the lower back. 
Numerous back injuries have been documented that have 
been caused by the nonfalling slipping or tripping accident. 
These can result in a variety of injuries— eccentric loading 
with muscle tears, muscle spasm, ligament damage, skeletal 
damage, or even disk damage. Any of these may occur alone 
or in combination. 

Table 6 describes the frequency of sudden movements 
in these injuries. The existence of sudden movement was 
determined from the interviews, with each case discussed 
before coding. Coding was positive if sudden movement 
clearly occurred at the time of injury, questionable if it may 
have been a factor, and negative otherwise. A separate code 
was assigned to those cases where the injured party was 
struck by a piece of falling top. 



Information on why the injured miner was performing 
the task is presented in table 5. In 87 pet of the injuries, 
it was simply a normal part of the job. The remaining 13 
pet were divided somewhat equally among six other 
categories. Filling in for someone else and having to do the 
task alone both accounted for 4 pet each. In two other in- 
stances, someone else failed to perform their task properly, 
thus leaving a hazardous situation in which another miner 
was injured. 

Table 5.— Reason for performing task, percent 

Reason 

Normal part of job 87 

Filling in for someone else 4 

No one else was available 4 

Someone else did task incorrectly 2 

High top or bad top 1 

Getting ready for visit 1 

Nonroutine (6 miners lifting) 1 

Total 100 

Other related information that was collected was 
whether the task was routine or not. In 92 pet of the cases, 
the task was defined as routine while the remaining situa- 
tions were evaluated as nonroutine. In one nonroutine in- 
stance, the top was bad and had to be removed, which 
created a roof height of over 10 ft. The roof bolter operator 



Table 6.— Sudden movement as a factor in back 
injuries, percent 

Category 

Sudden movement occurred 

Sudden movement may have occurred 

Sudden movement did not occur 

Struck by falling top 

Total 



54 

23 

17 

6 

100 



Most back injury statistics attribute the majority of the 
injuries to lifting, twisting, overloading, and so forth. There 
is definitely no question that these are major causes of back 
injuries, but they are not the only causes. In many cases, 
they are closely associated with sudden movements. For ex- 
ample, a lift is started, the hand slips on the load, the lifter 
tries to maneuver to regain control; the maneuver is not 
anticipated and an injury results. Another example is when 
carrying something, a worker's foot slips and causes a sud- 
den change in posture, thus resulting in an excessive 
loading to the body. 

More important is the fact that conventional coding 
systems do not include sudden movements in their causal 
coding scheme. Unfortunately, this means that sudden 
movements cannot be evaluated with respect to past acci- 
dent reports or injury analyses. The data collected to date 



in this project strongly suggest that this is a serious over- 
sight. More than 50 pet of the injuries investigated have 
clearly involved some type of sudden movement that 
resulted in unexpected (and thus unprepared for) loads on 
the body. Information on sudden movements became ob- 
vious only because of the data collection methodology of this 
project, that is, the in-depth questioning related to these 
back injuries. 

This paper is providing an interim summary of the 
research conducted thus far, as well as providing an indica- 
tion of what types of analyses will be done with the com- 
pleted data base for 200 injuries. Table 7 provides an 
analysis of injuries that involved lifting, holding, carrying, 
pulling, or pushing (the classic materials-handling designa- 
tions). The table was developed by first sorting the data by 
injury agent, then by whether sudden force release was in- 
volved, and then finally by whether the task was routine 
or not (whether the task was done every shift or even every 
day by someone at the mine). 

Of the 42 accidents listed in table 7, 27 involve a sud- 
den movement loading. Of these, 23 are routine tasks and 
4 are designated as nonroutine. The remaining 15 accidents 
do not involve any type of sudden movement loading. Four- 



teen of these are routine tasks and only one is considered 
a nonroutine task. 



Table 7.— Back injuries involving typical materials and 
equipment, analyzed by whether sudden body movements 
occurred or not, and whether the task was routine or not 



Materials and equipment 



Sudden 
movement 



Task 
routine Number 



Ventilation curtain . . . 

Spool of cable 

Timbers and headers . 
Rock duster 



Scoop panel and 1 0-st-capacity jack 
I-beam 



Wheelbarrow 

Cable and/or water line 

Light item, not specified 

Heavy item, not otherwise specified 



Roof bolt with or without half header 
5-gal containers of liquid 



Yes . 


Yes 


Yes . 


Yes . . 


No .. 


Yes 


Yes . 


No ... . 


Yes . 


Yes 


Yes . 


Yes . . 


No .. 


Yes . . 


Yes . 


Yes . . 


Yes . 


No . . . 


No .. 


Yes .. 


Yes . 


No . . . 


Yes . 


Yes .. 


No .. 


Yes .. 


Yes . 


Yes .. 


No .. 


No . . . 


No .. 


Yes .. 


Yes . 


No . . . 


Yes . 


Yes . . 


No .. 


Yes . . 


Yes . 


Yes . . 


Yes . 


Yes . . 



DISCUSSION 



This research has identified that sudden movement, 
caused by a wide variety of situations, is a major cause of 
back injuries in underground coal mining. As mentioned 
earlier, the sudden release of energy to the musculoskeletal 
system can be classified as the primary causal agent for 
these injuries. Trying to prevent these injuries seems to be 
an extremely difficult task, considering the diverse set of 
activities that were listed in the "Results" section. However, 
just having an awareness of these types of situations can 
help to change an unexpected condition to an expected con- 
dition, and thus reduce the loading to the lower back, as 
explained in the following. 

A recent research study (7) investigated the response 
of the back muscles during sudden, unexpected loading. The 
data collected during the unexpected loading were compared 
to the back-muscle response data collected (under the same 
test conditions) during sudden, expected loading. The data 
from this research study indicate that the unexpected con- 
ditions caused trunk-muscle reactions that resulted in 
greater loadings to the lower back than those encountered 
(under the same test conditions) when the loading was 
expected. 

The magnitude of the unexpected loads averaged 1.7 
times that of the expected loadings for the peak component 
of the muscle force, and 2.4 times the expected loading for 
the mean component of muscle force. These data indicate 
that the effect of unexpected loading essentially makes the 
muscles respond the same as they do to more than twice 
the weight during an expected loading situation. These find- 
ings indicate that if a person is aware of potentially hazard- 
ous conditions, and if some event occurs (slipping, tripping, 
jolt or bump, load slips in the grasp, and so forth), the body's 
reaction to it will be more controlled, and will result in less 
loading to the musculoskeletal system. 



One practical idea related to the unexpected-expected 
loading concept can be instituted rather easily. Haulageway 
conditions change constantly because of the dynamic nature 
of coal mining. In a matter of a few weeks or less, a good 
haul road can be in very rough shape because of its con- 
stant use; or a haul road may have to be relocated from an 
entry with good conditions to an entry with poor conditions. 

When rough conditions are encountered, a simple means 
of marking their location is to hang reflectors (or perhaps 
just one of a dramatic color) from a roof bolt plate. As con- 
ditions change, the reflectors can be moved or more added 
to mark new rough areas to alert the usual operators and 
to warn other operators who may be unfamiliar with the 
road conditions. Even a second or two of warning lets the 
body's natural protective mechanism tense the muscles to 
prevent a totally unexpected load to occur to the lower back. 

This idea is adapted from a film ("Visual Search in Driv- 
ing") developed for the Ohio Department of Transportation 
by The Ohio State University. One part of the film dealt 
with night driving and showed a dramatic improvement 
when a driver was told to make a turn at a street light in 
the distance as opposed to a certain cross street in the 
distance. The light source was easier to perceive and was 
a better reference point. Thus, it is apparent that a uniquely 
colored or shaped reflector positioned on the mine roof would 
serve as a warning to operators of equipment (in all sec- 
tions of the mine) of hazardous bottom conditions. 

In conclusion, both the miners and supervisors should 
be reminded to look for, identify, and consciously avoid 
potential sources of sudden, unexpected movement. Com- 
municating their observations to the other miners will be 
helpful and quite effective in reducing the potential for these 
types of back injuries. 



REFERENCES 



1. Stobbe, T.J., T.G. Bobick, and R.W. Plummer. Musculoskeletal In- 
juries in Underground Mining. Ann. ACGIH, v. 14, 1986, pp. 71-76. 

2. Mausner, J.S., and A.K. Bahn. Epidemiology: An Introductory Text. 
Saunders (Philadelphia), 1974, p. 3. 

3. Lilienfeld, A.M., and D.E. Lilienfeld. Foundations of Epidemiology. 
Oxford Univ. Press (New York), 2d ed., 1980, pp. 30-37. 

4. Smith, G.S. Injuries as a Preventable Disease: The Control of Oc- 
cupational Injuries From the Medical and Public Health Perspective. 
Abstracts from the International Conference on Musculoskeletal Injuries 
in the Workplace, W.H.O. Regional Office for Europe, Copenhagen, 
Denmark, May 27-29, 1986, p. 23. 



5. Peters, R.H. Activities and Objects Most Commonly Associated With 
Underground Coal Miners' Back Injuries. Paper in Back Injuries. Pro- 
ceedings: Bureau of Mines Technology Transfer Symposia, Pittsburgh, PA, 
August 9, 1983, and Reno, NV, August 15, 1983, comp. by J.M. Peay. 
BuMines IC 8948, 1983, pp. 23-31. 

6. Unger, R.L., and D.C Connelly. Materials Handling Methods and 
Problems in Underground Coal Mines. Paper in Back Injuries. Proceedings: 
Bureau of Mines Technology Transfer Symposia, Pittsburgh, PA, August 
9, 1983, and Reno, NV, August 15, 1983, comp. by J.M. Peay. BuMines 
IC 8948, 1983, pp. 3-22. 

7. Marras, W.S., S.L. Rangarajulu, and S.A. Lavender, Trunk Loading 
and Expectation. Ergonomics, v. 30, No. 3, Mar. 1987, pp. 549-560. 



APPENDIX— INJURED WORKER INFORMATION-OBSERVATION FORM- 
BACK INJURY RESEARCH PROJECT 

Case # 

ACCIDENT SUMMARY 

A 1 . Description of accident 



A 2 . Shift working at time of accident 
A 3 . Time of accident 



A 4 . What was being done at the time of injury? How? 



A 5 . Why was task being done? How did it relate to overall 
activity? Was it routine? 



A 6 . Why were you doing the task? (Normal part of job; just 
filling in; helping out; emergency; etc.) 



A 7 . Is there a standard method for the task? (SWI, JSA, etc.) 
What is it? What related training did you have? 



A 8 . If A4 and A7 are different, why? 



A9. Would A7 have improved the situation? 



A 1 . Are there alternative methods for the task? Describe and evaluate. (Hoist, etc.) 
Why weren't they used? 



All. How many normally do the task? This time 

If different, why? 



A 1 2 . If more than one miner was involved, was (were) the other miner(s) a factor in the injury? How or why? 



A 1 3 . Was the lack of communications or training a factor? 



A 1 4 . Does the task have any special hazards? 



A 1 5 . Was equipment involved? How? Design factors? 



A 1 6 . How could the situation be avoided in the future? 



MATERIAL HANDLING SUMMARY 

B 1 . Describe the load (size, shape, center of gravity.) Stable? Slippery? Handles? (their shape and location, 
etc.). If shoveling, what is typical load? How is it handled? Shovel design? 



10 



B 2 . Where was the load? 



At start of movement At end 

B 3 . How was load grasped (specify hand position) 



B4. Weight 



B 5 . Bottom (ground, floor) condition 



B 6 . Obstruction(s) to movement of load 



B 7 . Obstruction(s) to movement of body (equipment, housekeeping) . 



B 8 . Mine height at injury site (use posture-based estimate) 



B9. Push? Pull? Lift? Lower? 



BIO. Handling frequency (estimate) and normalizer (per hour, per shift, per stopping, etc.) 



B 1 1 . Lifting technique (normally, this time, forward or backward curve to the trunk) 



B 1 2 . If not normal, why not? 



B 1 3 . Body posture at time of injury (sketch) 

B 1 4 . Material handling summary of current job (tasks, loading, frequency, mean, and range) 



B 1 5 . Environmental conditions. Lighting 



Noisy? Describe if possible 

Dusty? Other? 



B 1 6 . Working overtime? 



B 1 7 . If yes, what was done during regular work shift? 



11 



INJURY SUMMARY 

C 1 . Describe the injury (what did you feel, where, when— relate this to accident description) 

C 2 . Location of pain 



C 3 . Description of pain 



C 4 . Examination procedure 



C 5 . Treatment received 
C 6 . Diagnosis 



C 7 . Physical therapy or medication 



C 8 . Prescription 

C 9 . Injured's opinion of injury cause 



PERSONAL DATA SUMMARY 



D 1 . Age 
D2. Sex 



D3. Job title 



D 4 . Job working at the time of the injury 



D 5 . Experience with the task being done at the time of the injury 



D 6 . Height and weight 



D 7 . Physique and physical fitness (subjective estimate) 



D8. Grip strength results Rl R2 LI L2 

(Circle preferred hand) 
D 9 . Other strength results 



12 



HISTORICAL SUMMARY 

E 1 . Mining-related work history: 

Job title No. of years 

Lifting, material-handling activity 



Job title No. of years 

Lifting, material-handling activity 



Job title No. of years 

Lifting, material-handling activity 



Job title No. of years 

Lifting, material-handling activity 



E 2 . Nonmining-related work history: 

Job title No. of years 

Lifting, material-handling activity 



Job title No. of years 

Lifting, material-handling activity 



Job title No. of years 

Lifting, material-handling activity 



E 3 . History of all types of strains and sprains 



E 4 . Leisure activities 



13 



ANALYSES OF MATERIALS-HANDLING 
SYSTEMS IN UNDERGROUND LOW-COAL MINES 



By Thomas G. Bobick 1 



ABSTRACT 



Task analyses were conducted by the Bureau of Mines at four underground low- 
seam coal mines to evaluate their supply-handling systems and for use in subsequent 
design of laboratory simulation experiments. Items were tracked (by videotaping) from 
delivery to the surface storage areas to their final destinations underground. Of par- 
ticular interest were those tasks that required manual handling of supplies or equip- 
ment. Analysis of the videotapes revealed that the miners handled materials while 
stooped over a total of 37.8 pet of the time, 31.5 pet while on both knees, and 9.5 pet 
while kneeling on one knee. These working postures impose considerable stress on the 
lumbar spine and may be implicated in the high number of back injuries in this work 
population. 

This paper also discusses various mechanical-assist devices developed by the Bureau 
and successfully evaluated in the underground workplace. These devices can be used 
to minimize the manual effort and the corresponding risk of injury associated with han- 
dling supplies and equipment components in low-seam coal mines. 



INTRODUCTION 



Underground miners who must work in low-seam coal 
mines «48-in roof height) often handle heavy materials in 
kneeling or stooped postures. Both of these postures are 
known to produce considerable loads on the lumbar spine 
and may be a reason for the high number of back injuries 
in the mining environment. 

Approximately 70 pet of all miners will have some time 
off with back pain during their career (1 ). 2 Approximately 
25 pet of all mining injuries involve trauma to the back (2). 
Considering severity, back injuries have an average of 19.3 
lost workdays per injury (3). Between 55 and 60 pet of these 
back injuries are due to overexertion during materials- 
handling activities (3). 

The Bureau is currently conducting an in-house project 
to determine the stresses associated with lifting in work 
postures characteristically assumed in low-coal mines. Task 
analyses, which were conducted in four underground low- 
seam coal mines, were used to design a laboratory study 
that simulated repetitive lifting tasks under controlled 
conditions. 

An important support activity for underground mining 
is the transfer of supplies and equipment from the surface 
storage areas to the underground locations where they are 



'Mining engineer, Pittsburgh Research Center, Bureau of Mines, Pitts- 
burgh, PA. 

2 Italic numbers in parentheses refer to items in the list of references at 
the end of this paper. 



needed. Typically, 20 to 30 pet of the total underground 
workforce is involved exclusively in handling supplies; 
however, virtually all underground miners are occasion- 
ally required to manually lift and transport parts, supplies, 
or equipment. The techniques for handling supplies in the 
underground environment, whether manually or 
mechanically, can vary extensively depending on the en- 
vironmental conditions, the available equipment, and cur- 
rent management practices. 

To identify the various factors that characterize the 
materials-handling problems, a task or job analysis is 
necessary. Job analysis has been defined (4) as "a method 
of gathering pertinent facts about worker[s] and [their] 
work. The method to be used varies, depending upon the 
objective of the study." A job or task analysis usually con- 
sists of a detailed listing of activities in some systematic 
order, generally in the sequence that they occur in the job. 

Task analyses were conducted in three low-seam coal 
mines located in eastern Kentucky and one low-seam coal 
mine in central Pennsylvania. Different job classifications 
that required workers to manually handle supplies or equip- 
ment as part of their normal job duties were documented. 
The focus of the task analysis was to determine the extent 
to which low-seam coal miners conducted their manual 
materials-handling activities in stooped-over or kneeling 
postures. 

Research has been conducted that has shown that the 
stooped posture increases the pressure in the disks of the 



14 



lumbar spine (5-6). The possibility of damaging a disk in- 
creases when an individual is performing materials- 
handling activities with a severely bent back (7-8). Han- 
dling materials while kneeling is also stressful to both the 
disks and the vertebras of the spinal column, because of the 
twisting motion that is employed in this posture (9). The 
torsos of these workers twist because their knees cannot 
be easily repositioned to prevent trunk rotation. 

Other research has indicated that twisting can cause 
an unsymmetrical distribution of forces on the disks of the 
lumbar spine (10), and can actually be more hazardous to 
the lower back than severe bending alone (11). In fact, the 
Work Practices Guide for Manual Lifting, developed by the 



National Institute for Occupational Safety and Health, sug- 
gests that a worker should never twist while lifting (12). 
While a great deal of research has focused on developing 
lifting limits for unrestricted work postures (12), very little 
research has studied the problems associated with lifting 
materials in restricted work postures (13). 

The objective of this study was to conduct a task analysis 
at several low-seam coal mines to document the supply- 
handling activities so experimental studies, which would 
investigate the physiological and biomechanical responses 
to handling materials in kneeling and stooped postures, 
could be designed and conducted in a realistic manner. 



BACKGROUND 



The National Coal Board of Great Britain refers to the 
analysis of the factors that affect performance of any job 
as work study. Work study is defined (14) as "the systematic 
examination of activities ... to improve the effective use 
of human and other material resources." Many different 
techniques can be used to conduct a task analysis, since 
there is a wide variety of jobs to be analyzed. Task analysis 
is useful in structuring jobs, investigating accidents, defin- 
ing personnel requirements, describing job duties, or 
developing training programs. Some researchers have listed 
as many as 20 major categories to which a task analysis 
can be applied (4). 

Because the underground mining environment is quite 
different from the typical industrial workplace, the task 
analyses that are utilized are unique to that industry. Many 
task analysis techniques used in factories or other similar 
work environments are not applicable to the underground 
environment. In a manufacturing workplace, observers can 
usually position themselves so they will not interfere with 
the job activities, and the workplace is usually well il- 
luminated so a mobile worker can be followed and 
photographed fairly easily. The optimum situation is when 
the observer can remain unnoticed while conducting the job 
analysis, thus not biasing the results. 

The underground mining environment, however, pro- 
vides unique problems for researchers conducting a task 
analysis. Area illumination is provided only by the limited 
number of production and haulage machines. Personal il- 
lumination is provided by battery-powered cap lamps worn 
on hard hats. When videotape is used to film the materials- 
handling activities, the miners are aware of the start of tap- 
ing because of the bright light required for the filming ac- 
tivity. Unfortunately, the use of this light, combined with 
the fact that the investigators could not conduct the study 
without being observed by the miners, may have caused the 
miners to alter their daily activities, thus affecting the task 
analysis. Efforts were made to assure the 10 or 12 miners 
on the section crew that the study was not a productivity 
study and that the results would not adversely affect their 
jobs. Despite these assurances, however, there was no way 
to evaluate whether the miners altered their work patterns 
to create a positive effect for management, since it was not 
possible to observe a control group without causing the same 
problem. Future studies will be conducted using more 
sophisticated video equipment that requires less light, thus 
making the presence of the investigators less obvious. 

An early study funded by the Bureau (15) described the 
underground operating environment in terms of five 



separate supply-handling functions: (1) production end use 
(supply items used at the working face), (2) production sup- 
ply (supplies moved from surface storage to near the work- 
ing face, but excluding end use), (3) section move (handling 
supplies during the process of moving a production unit to 
a new section of the mine), (4) equipment maintenance (sup- 
plies or parts needed for maintenance of mining equipment), 
and (5) mine maintenance (supplies needed for permanent 
maintenance of the mine). 

Accidents during the production supply activities 
represented 49.4 pet of the total accidents in the 22 mines 
that were visited during this early research program (15). 
The remaining 50.6 pet of the accidents were divided among 
the other four categories almost equally— 11.2 pet for pro- 
duction end use, 13.0 pet for section move, 16.4 pet for equip- 
ment maintenance, and 10.0 pet for mine maintenance 
activities. 

There are several types of daily supplies of different 
weights and sizes involved in the production and mine 
maintenance supply functions. Table 1, which is taken from 
reference 15, provides a typical list of supply items and cor- 
responding weights. 



Table 1 .—Weights of supplies commonly handled in 
underground coal mines, pounds 

2- to 12-ft roof bolts, plates, and shells 4-12 

Rock-dust bags 50 

2- by 6-in to 6- by 8-in, 1- to 16-ft lengths of timber, boards, 

and headers 8-270 

16- by 8- by 4- or 6-in stopping blocks 27-65 

5-gal oil container 40 

4- to 10-in-diam, 3- to 15-ft-long round timber posts 34-320 

1- to 6-ft crib block 20-60 

Mortar mix bags 90 



Figure 1 shows a typical supply -handling activity in low 
coal— a miner is ready to throw a 6- by 6-in cribbing block 
weighing approximately 35 lb. The kneeling posture im- 
poses considerable torsional stress on the lower back 
because the workers cannot easily reposition their knees. 

METHOD 

A task analysis was performed at three small (two sec- 
tions each) low-seam (roof heights <48 in) underground coal 
mines in eastern Kentucky during 1984 and one large (11 
sections) low-seam coal mine in central Pennsylvania dur- 
ing 1985. Videotape was used to document the materials- 
handling activities of workers in these mines according to 



15 




Figure 1.— Low-seam coal miner ready to throw a 6- by 6-in 
cribbing block, weighing approximately 35 lb. The kneeling pos- 
ture imposes considerable torsional stress on the lower back 
because the workers cannot easily reposition their bodies. 



the previously described five major supply-handling 
categories. 

During 24 mine visits (12 in Kentucky and 12 in Penn- 
sylvania), an attempt was made to document as many 
supply-handling activities as possible given the time con- 
straints and the availability of activities that could be 
filmed. A listing of most of the materials-handling tasks 
(broken down by supply-handling function) filmed during 
the Kentucky visits is provided in table 2. Table 3 provides 
the breakdown for the Pennsylvania mine visits. Of course, 
these are the tasks that the survey crew was able to docu- 
ment during the mine visits. This does not imply that these 
tasks are more important than others that might not be 
listed. Often the crew would be just a little too late or too 
early to videotape other equally important manual-handling 
tasks. 



Table 2.— Supply-handling function tasks filmed at three 
Kentucky mines 

Function Task 

Equipment maintenance . . . Removing continuous miner gathering arm 
motor. 

Section move Advancing conveyor belt. 

Production end use Hanging ventilation curtain. 

Throwing rock dust. 

Handling or pulling power cables. 

Setting timbers. 

Installing roof bolts. 
Production supply Unloading root bolts and plates. 

Loading and unloading concrete blocks. 

Loading and unloading rock-dust bags. 

Mine maintenance Installing heavy wooden roof-support 

beams, 10- by 10-in by 12-ft. 

Installing 16-ft I-beam. 

Installing roof-support cribbing. 

Building concrete block ventilation 
stopping. 



Table 3.— Supply-handling function tasks filmed at 
one Pennsylvania mine 

Function Task 

Equipment maintenance . . . Removing servopump from continuous 
miner. 

Section move Advancing conveyor belt. 

Production end use Throwing rock dust. 

Setting timbers. 

Installing roof bolts. 

Handling or pulling power cables. 

Production supply Loading rock-dust bags onto supply cars. 

Loading timbers into scoop from supply 
car. 

Loading roof bolts and resin onto small 
scoop. 

Unloading roof bolts and resin at face 
area. 
Unloading rock-dust bags. 

Mine maintenance Building a concrete block ventilation 

stopping using both 65-lb solid blocks 
and 27-lb hollow core blocks. 
Laying rail; moving rail into place by 
manually sliding and by using a pry bar. 
Unloading and carrying 3- by 8-in by 18-ft- 
long wooden planks for roof control. 
Installing a series of roof-support 
cribbings. 



GENERAL DESCRIPTION OF THE SUPPLY- 
HANDLING SYSTEMS 

The equipment used to handle supplies at these mines 
included battery locomotives and tractors, scoops and mine 
jeeps, rail-mounted and rubber-tired flatcars and trailers, 
and shuttle cars. The production supply activity observed 
in these task analyses indicated that two distinct systems 
were utilized. The methods used were different mostly 
because of the size of the mines. 

The three mines in eastern Kentucky were all small 
operations that consisted of only two continuous miner sec- 
tions in each mine, and operated two shifts per day. The 
midnight shift was strictly for maintenance. The mine in 
central Pennsylvania consisted of 11 production sections; 
1 of these was a longwall operation and the other 10 were 
continuous miner sections. This mine operated three shifts 
a day, with maintenance being conducted whenever it was 
needed. A spare section was available and could be put in- 
to operation if another section was down for a long time 
because of extensive maintenance. 

The surface supply yards at the three small mines were, 
to some extent, unorganized and mismanaged. A forklift 



was available at one supply yard, but the rough terrain and 
the haphazard layout of the yard usually made its use im- 
possible. In fact, the task analysis crew observed two 
workers manually rolling a large wooden beam (10 by 10 
in by 12 ft, 250 lb) onto the forks because the forklift could 
not remove it from the storage pile that was in disarray. 
Thus, supplies were generally loaded and unloaded by hand. 

Concrete blocks and rock-dust bags were delivered to 
the surface storage area unpalletized. These items often had 
to be handled twice before they were loaded onto the sup- 
ply train to go underground. Because the company had 
only a limited number of supply cars, they had to be un- 
loaded at a central location so the empties could be taken 
back to the surface for reloading. 

Unloading of the supplies was accomplished manually 
by two workers. To move the supplies from the central 
storage area to the end-use location, they were reloaded onto 
a scoop vehicle (which could unload them mechanically with 
the pusher plate of the bucket) or a shuttle car from which 
the supplies had to be manually unloaded. Thus, each block 
or bag was manually lifted and lowered four or five times; 
this unnecessary handling increases the risk of 



16 



musculoskeletal injuries to the miners and, of course, 
materials breakage and waste. 

In contrast, the surface supply yard at the central Penn- 
sylvania mine was very organized and well managed. The 
physical layout of the supplies facilitated the use of forklifts 
or front-end loaders to handle virtually all supplies by 
mechanical means directly onto the supply train. There 
were, however, some instances when some supplies had to 
be manually handled. The most notable exceptions were the 
rock-dust bags and supplies like wooden planks, crib blocks, 
and bundles of wedges that had to be rearranged and leveled 
off in the supply cars so the pile would be more stable or 
other items could be laid on top of them. 

The rock-dust bags were delivered to the storage yard 
by tractor-trailer at least once a day (often twice a day). The 
number of bags ranged from 600 to 800 per load. Two 
workers unloaded them directly onto two supply cars. 
Because this was a large mine, extra supply cars were 
available. Thus, cars could be left on a rail siding in each 
production section. As supplies were needed, the supply 
workers would use the scoop vehicle to transport supplies 
from the rail siding to the face area. Rock-dust bags would 
then be handled only twice from the surface to the end-use 
locations. The potential for an injury to a worker or 
breakage to the bags was, therefore, reduced by 50 to 60 



pet of that at the smaller mines that had to constantly reuse 
their supply cars. 

In addition to videotape, other techniques used to gather 
information on manually handling supplies at these mines 
involved interviews, on-site observations, still photography, 
and analysis of previous accidents. 

The videotapes were analyzed to determine the postures 
used by low-coal miners for the various underground 
materials-handling tasks. Additionally, an analysis was 
conducted of the frequency (lifts per minute) of the 
materials-handling tasks that involved repetitive handling 
of loads, using the tasks documented on videotape. Results 
from these two analyses are presented in the following 
section. 

During the visits to the mine sites, permission was 
received to collect data from the accident reports pertain- 
ing to back injuries that occurred during the previous year. 
Information was collected on back injuries that occurred at 
the Kentucky mines during 1983 and at the Pennsylvania 
mine during 1984. Subsequently, an analysis was conducted 
to determine the percentage of these accidents that in- 
volved materials-handling activities at a low lifting fre- 
quency «4 lifts/min), and those accidents that involved a 
high lifting frequency (>4 lifts/min). 



RESULTS 



The results of the videotape analysis on postures utilized 
during underground materials-handling activities in the 
four mines are presented in table 4. The predominant 
posture used while handling materials in these mines was 
stooped over (37.8 pet of total time on videotape). Kneeling 
on two knees was used for handling materials in 31.5 pet 
of all the videotaped materials-handling activities. Quite 
surprisingly, the next most often utilized posture was stand- 
ing (13.4 pet), which was a result of the seam conditions en- 
countered in the Pennsylvania mine. 

The average seam thickness in the Pennsylvania mine 
ranged from 41 to 47 in. There were, however, numerous 
areas in this mine where work was conducted when the 
seam thickness increased or when bad top was being 
stabilized and supported. For example, over 35 pet of the 
total time videotaped of the Pennsylvania miners working 
upright (standing) was related to the installation of roof- 
support cribbings. Other activities in which these workers 
were standing were track maintenance activities and roof 
bolting. 

The three Kentucky mines were operating in coal seams 
that were 36 to 42 in thick. Because of this more restricted 
posture, the miners worked while kneeling on two knees 
considerably more often than they did in the stooped 
posture. Conversely, the Pennsylvania miners tended to 
take advantage of the extra clearance they had and spent 
considerably more time working in a stooped position than 
while kneeling. 

Table 5 presents data regarding the frequency of lift for 
various materials that require repetitive handling. As 
shown in this table, the highest frequencies were for 



unloading concrete block from a supply car (approximate- 
ly 16 lifts/min) and unloading roof bolt plates, two or three 
at a time from a supply car (approximately 15 lifts/min). 
Handling rock-dust bags and cribbing block averaged about 
10 to 11 lifts/min, and unloading roof bolts and handling 



Table 4.— Time on film of postures assumed, during all 
manual-handling tasks, percent 

Posture Kentucky 1 Pennsylvania 2 ^SlS? 

Stooped 23^2 46/7 37.8 

2 knees 53.3 18.1 31.5 

Standing 5.6 18.1 13.4 

1 knee 12.9 7.4 9.5 

Sitting 3.1 8.1 6.2 

Squatting 1.8 1J5 1.6 

Total "99.9 "99.9 100.0 

1 Based on 167.6 min of videotape. 

2 Based on 273.8 min of videotape. 

3 Based on 441 .4 min of videotape. 

4 Does not add to 100 pet because of independent rounding. 



Table 5.— Lifting frequencies associated with repetitive tasks 

Time per lift, s Approx 

Range lifts/min 



Supplies Mean 

Unloading supply car: 

Roof bolts 9.12 

Rock-dust bags 5.27 

Roof bolt plates 3.92 

Concrete blocks 3.74 

Building ventilation stopping: 

Handling concrete blocks 9.91 

Building roof-support cribbing: 

Handling wooden crib blocks .... 6.12 



7.35-13.15 
4.99- 5.41 
3.19- 5.10 
3.42- 4.08 

8.19-14.40 

4.84- 6.92 



6- 7 

11-12 

15-16 

16 



9-10 



17 



concrete blocks during the building of a ventilation stop- 
ping averaged about 6 to 7 lifts/min. 

Results of the analysis of accident records for the eastern 
Kentucky mines are presented in table 6. Of the 27 back 
injuries that occurred at these mines during 1983, 48.1 pet 
were caused by lifts requiring heavy static exertions, 33.3 
pet were caused by repetitive lifting tasks, and 18.5 pet were 
not the result of lifting activities. 



Table 6.— Summary of accident records: Handling 

materials and back injuries at an eastern Kentucky coal 

company, 1983 

Category Injuries Share of total, pet 

Heavy static exertions 13 48.1 

Repetitive lifting 9 33.3 

Other (struck by, struck against, etc) 5 18.5 

Total 27 1 99.9 

1 Does not add to 100 pet because of independent rounding. 



DISCUSSION 



Several manual-handling activities were identified on 
the videotapes that could be either eliminated or modified 
to reduce the potential for a back injury. Examples include 
manually unloading roof bolts, and manually lifting and 
holding heavy roof-support beams. 

Roof bolts were delivered to one of the three Kentucky 
mines in wire-wrapped bundles of 500 bolts. These were 
loaded on the supply car (on the surface) by a forklift. The 
wire straps were then cut to allow the bolts to spread out 
so they could clear a low-roof area of the mine along the 
main haulageway. However, this meant that the bolts had 
to be manually unloaded underground, three or four at a 
time. What would have been a 1-min task using mechanical 
means (a chain attached to the scoop bucket) was turned 
into a 15- or 20-min task that involved lifting, twisting, and 
potential pinching hazards. The Bureau's recommendation 
was to contact the vendor and request that the bolts be 
delivered in bundles of 200 or 250. The smaller bundles 
could then clear the low area along the haulageway. Thus, 
the bolts could remain strapped together, permitting the 
workers to use the scoop to pull the bundles off the supply 
car to the section storage area, saving time and eliminating 
manual handling. 

Many of the more hazardous manual-handling tasks oc- 
cur during mine and equipment maintenance. In an attempt 
to address these problems, the Bureau has designed and 
fabricated specialized mechanical-assist devices to help with 
the more difficult jobs. Each device is relatively inexpen- 
sive and can be built in any reasonably equipped mine shop. 
This should encourage a company to fabricate enough of 
the devices to be generally useful. Three of the devices 
developed thus far include the following. 

1. Mine jack-wheel changer.— This device (fig. 2) is the 
underground version of the floor jack found in most surface 
maintenance shops. High-flotation tires provide quick 
transport and positioning in wet or rocky bottom, and the 
fore-and-aft and rotational adjustments of the saddle per- 
mit easy alignment of the bolt holes. With a jack of this 
type, a shuttle car tire, a motor, or a transmission can be 
removed and replaced with a minimal amount of manual 
handling. 

2. Pivot boom.— This device (fig. 3) is an adaptation of 
a common device found on many pickup trucks. It can be 
used to drag, lift, and position (swing) loads weighing up 
to 500 lb that are adjacent to any machine. 

3. Beam-raising vehicle.— I-beams, sections of rail, and 
heavy wooden crossbeams are often installed in 
haulageways that need extensive roof support. The wooden 
beams, ranging in size from 8 by 8 in to 12 by 12 in, with 
lengths varying between 10 and 16 ft, can weigh from 200 
to 300 lb. The sections of rail are usually 15 ft in length, 
and the size used will vary from 80 to 105 lb (per 3-ft length). 



Thus, the total weight of a section of rail can range from 
400 to 525 lb. The I-beams used for this type of roof sup- 
port will typically weigh as much as the sections of rail. 
During the mine visits in eastern Kentucky, videotapes 
were taken of the installation of two 10- by 10-in by 12-ft 
wooden beams and a 6-in I-beam, approximately 16 ft long. 
These were both lifted and manually held until the support 
timbers were installed at each end. The wooden beam was 
lifted by three workers, two at one end and a single massive 
employee who supported the other end on his back while 
he was bent over in a stooped posture. The I-beam was lifted 
and supported by five workers. 

As a result of these observations, two Bureau re- 
searchers designed a special vehicle (fig. 4), which can be 
either rail-mounted or equipped with rubber tires, that uses 
a movable hydraulic jack to safely lift crossbeams, I-beams, 
or sections of rail to the mine roof and position them for 
permanent installation (fig. 5). The hydraulic jack is re- 
cessed into the vehicle so that it can serve as a regular flat 
car for hauling supplies when it is not being used for beam 
installation. Additionally, the jack can be rolled back and 
forth along the length of the car while the jack arm is in 
a raised position. This permits the positioning of the beam 
to its proper location without moving the entire car. 

The end of the arm that supports the beam can be 
rotated through 360° in a horizontal plane (parallel to the 
floor and roof). The capability of rotating the beam-support 
head increases the ease with which the heavy, awkward 
beams can be maneuvered. Essentially, this device will per- 
mit the beams to be safely installed by only two workers- 
one to balance the beam on the support head and the other 
to operate the jack to raise the beam to the roof. This vehi- 
cle is presently being field tested in an eastern Ohio coal 
mine (fig. 5) where it has been favorably received and has 
been used regularly for the past year. 

The majority of the supply -handling tasks, however, are 
of such a nature that individual items are handled 
repetitively. It is these types of tasks, such as handling rock- 
dust bags, concrete blocks, or wooden crib blocks, that are 
serving as the basis for simulation experiments in the 
Bureau's ergonomics laboratory. Laboratory simulation 
allows controlled biomechanical, physiological, and 
psychophysical evaluation of the tasks; thus, an indication 
of the strenuousness of the activities can be determined. 
The task analyses conducted at four mines indicated 
that underground miners typically work in a stooped-over 
posture, or while kneeling on both knees. Therefore, the on- 
going laboratory research has been designed to look at the 
physiological effects on low-seam coal miners as they lift 
in stooped and kneeling postures under controlled 
conditions. 



18 




Figure 2.— Prototype mine jack-wheel changer during capacity testing with a 1,500-lb block. 




Figure 3.— Underground testing cf the pivot boom, which has a 500-lb lifting capacity. 



19 




Figure 4.— Shop testing of the beam-raising vehicle. 




Figure 5.— Installation of a 15-ft section of rail (weighing 525 lb) in an eastern Ohio coal mine. 



20 



SUMMARY 



The task analyses, which were conducted on the supply- 
handling systems of the different cooperating mines, in- 
dicated the importance of having a systems approach (han- 
dling palletized or unitized supplies) to the movement of 
materials. The videotapes were valuable for defining and 
analyzing the postures that the miners assumed while per- 
forming their normal daily routine. The task analysis was 
a necessary step in designing the experiments that are be- 



ing conducted in the laboratory. Analysis of the tapes in- 
dicated that approximately 15 to 20 pet of the manual- 
handling tasks could probably be eliminated or modified 
by existing or easily designed and fabricated mechanical- 
assist devices, such as the Bureau-designed beam-raising 
vehicle, which if used to lift and assist in the installation 
of heavy roof-support beams could prevent potential back 
injuries. 



REFERENCES 



1. McDonald, E. B., R. Porter, C. Hibbart, and J. Hart. The Rela- 
tionship Between Spinal Diameter and Back Pain in Coal Miners. 
J. Occup. Med., v. 26, No. 1, 1984, pp. 23-28. 

2. Peay, J. M. (comp.) Back Injuries. Proceedings: Bureau of 
Mines Technology Transfer Symposia, Pittsburgh, PA, August 9, 
1983, and Reno, NV, August 15, 1983. BuMines IC 8948, 1983, 110 
pp. 

3. Stobbe, T. J., T. G. Bobick, and R. W. Plummer. 
Musculoskeletal Injuries in Underground Mining. Paper in Ann. 
of ACGIH, v. 14 (Int. Conf. on the Health of Miners), 1986, pp. 71-76. 

4. Zerga, J. E. Job Analysis, A Resume and Bibliography. J. 
Appl. Psychology, v. 27, 1943, pp. 249-267. 

5. Nachemson, A. L. The Lumbar Spine: An Orthopaedic 
Challenge. Spine, v. 1, No. 1, 1976, pp. 59-71. 

6. Fiorini, G. T., and D. McCammond. Forces on Lumbo- 
Vertebral Facets. Ann. Biomech. Eng., v. 4, 1976, pp. 354-363. 

7. Kramer, J. Intervertebral Disk Diseases. Yearbook Med. 
Publ., 1981, 221 pp. 

8. Adams, M. A., and W. C. Hutton. The Effect of Posture on 
the Strength of the Lumbar Spine. Eng. Med., v. 10, No. 4, 1981, 
pp. 199-202. 



9. Lepore, B. A., and C. Lepore. The Employer's Back Injury 
Prevention Handbook. Bridgeview Books, 1983, 142 pp. 

10. Andersson, G. B. J. Permissible Loads: Biomechanical Con- 
siderations. Ergonomics, v. 28, No. 1, 1985, pp. 323-326. 

11. Gracovetsky, S., and H. F. Farfan. The Optimum Spine. 
Spine, v. 11, No. 6, 1986, pp. 543-573. 

12. U.S. Department of Health and Human Services. Work Prac- 
tices Guide for Manual Lifting. NIOSH Publ. 81-122, 1981, 183 pp. 

13. Gallagher, S. Back Injury Research at the U.S. Bureau of 
Mines Ergonomics Laboratory. Paper in Proceedings of the Col- 
legiate Association for Mining Education (4th Annu. Meet., Rolla, 
MO, October 3-4, 1985), pp. 170-191. 

14. National Coal Board Mining Department (United Kingdom). 
Work Study in Mines. 1979, 275 pp. 

15. Diaz, R. A., and A. Chitaley. System for Handling Supplies 
in Underground Coal Mines. Ongoing BuMines contract H0188049; 
for inf., contact R. Unger, TPO, BuMines, Pittsburgh, PA. 

16. Foote, A. L., and J. S. Shaefer. Mine Materials Handling 
Vehicle (MMHV) (contract H0242015, MB Associates). BuMines 
OFR 59-80, 1978, 308 pp.; NTIS PB 80-178890. 



21 



BACK STRENGTH AND LIFTING CAPACITY OF UNDERGROUND MINERS 



By Sean Gallagher 1 



ABSTRACT 

The Bureau of Mines is conducting research to establish recommendations for reduc- 
ing the incidence and cost of back injuries due to manual materials-handling (MMH) 
activities in low-seam coal mines. Typically, 55 to 60 pet of all back injuries suffered 
in the mining industry are a result of overexertion during manual lifting tasks. While 
many lifting studies have been performed relating to other industrial environments, 
few studies have addressed the unique stresses of lifting in the low-coal mining 
environment. 

This paper summarizes Bureau research that has examined the physiological, 
biomechanical, and psychophysical stresses associated with lifting in the restricted work- 
ing postures used by miners in low-coal mines. The implications of the findings of these 
2-yr studies are discussed, and preliminary recommendations for lifting in low-seam 
coal are presented. 



INTRODUCTION 



Underground miners who work in low-seam coal mines 
«48-in roof height) often lift heavy materials in severely 
restricted work postures. The two postures most often used 
during MMH activities in low-seam mines are stooped and 
kneeling (I). 2 Each of these postures cause considerable 
stress to the spine, and may help to explain the high in- 
cidence of low-back pain (LBP) in the mining industry. For 
example, the stooped posture (which causes the spine to be 
severely flexed) has been shown to substantially increase 
the pressure on the shock-absorbing disks of the spine (2). 
This increased pressure will cause the disk to deform and 
may cause the back of the disk to protrude and impinge 
upon the spinal nerves, which will result in LBP (3). The 
kneeling posture, on the other hand, causes the miner to 
use a twisting motion of the trunk to accomplish a lift (ow- 
ing to the limited mobility afforded by working on one's 
knees). The torsional load experienced by the spine when 
the trunk is twisted has recently become much more 
recognized as a significant mode of injury to the low-back 
(i.e., lumbar) region of the spine (4). Therefore, the postures 
most often used to lift materials in the low-coal environ- 
ment cause the miner to perform what are generally regard- 
ed as the two worst actions in terms of causing LBP: bend- 
ing and twisting (3-5). 



1 Research physiologist, Pittsburgh Research Center, Bureau of Mines, 
Pittsburgh, PA. 

2 Italic numbers in parentheses refer items in the list of references at the 
end of this paper. 



Many researchers have attempted to develop lifting 
limits for materials handling in unrestricted work postures 
(6-8). However, very little research has been performed that 
has studied the problems associated with lifting materials 
in restricted postures (9). Traditionally, three approaches 
have been used to set lifting limits: the physiological ap- 
proach, the biomechanical approach, and the psychological 
approach (1, 10). 

The physiological approach uses measurements such as 
heart rate or oxygen consumption as indexes of the 
heaviness of work performed, while the biomechanical ap- 
proach attempts to calculate the compressive and shear 
forces on the disks of the lumbar spine. However, using 
either of these two approaches alone may be misleading 
because both physiological and biomechanical stresses are 
involved in all lifting tasks. The psychophysical approach 
uses subjective estimates of acceptable weight-lifting 
burdens in an effort to integrate the physiological and 
biomechanical stresses inherent in a lifting task (10). 

In the Bureau's development of lifting recommendations 
for low-seam coal mines, a combination of methods of 
establishing acceptable lifting limits has been used. This 
paper presents the results of Bureau research examining 
(a) maximum acceptable weights of lift (MAWL) in restricted 
lifting postures, (b) back strength capabilities of 
underground miners, and (c) the physiological stresses of 
lifting in restricted postures (especially with regard to 
prevention of muscular fatigue). 



22 



MAXIMUM ACCEPTABLE WEIGHTS OF LIFT 
IN STOOPED AND KNEELING POSTURES 



Eleven healthy male underground miners [mean age (M) 
= 36 yr, ±8 yr standard deviation (SD)] participated in a 
study to examine the effects of posture on lifting capacity. 
Subjects were volunteers from low-seam coal mines and 
were experienced with handling materials in restricted 
work postures. Each subject was asked to adjust the weight 
in a 20- by 13- by 7-in lifting box according to his estimate 
of lifting capacity for each posture (stooped or kneeling). The 
lifting tasks were performed under an adjustable-height 
mine simulator that restricted the subject's posture. The 
height of the simulator was set at 48 in for this study. Figure 
1 is a schematic of a subject performing the lifting task in 
the stooped posture. 

Lifting instructions were given to the subject before the 
experiment started. In this study, the subjects were told to 
adjust the weight in the box so the load could be handled 
for a 20-min period (the actual lifting period) and to assume 
that this 20 min of lifting would have to be performed four 
times during a workday. The subject lifted the box at a fre- 
quency of 10 lifts/min for two 20-min periods in each 
posture. One period started with a heavy box, weighing ap- 
proximately 95 lb, and the other with a light box, weighing 
approximately 15 lb, to control for bias due to initial start- 
ing weight of the box. A 10-min rest break was provided 
between tests so that subjects could rest and/or attend to 
personal needs. The average subjectively determined weight 
chosen for the two test conditions in a posture was taken 
as the maximum acceptable weight of lift (MAWL) for that 
posture. Two additional 10-min lifting periods were included 
to observe the physiological responses of lifting a 50-lb box 
in each posture. 

The primary dependent measures for the psychophysical 
lifting study were the MAWL for the kneeling and stooped 
postures. Secondary dependent measures included heart 
rate (HR), oxygen utilization (V0 2 ), and ventilation volume 
(V E )- Heart rate was obtained during the last 10 s of every 
minute using a Beckman Dynograph Recorder, 3 model 
511-A. The average heart rate for each condition was taken 



3 Reference to specific products does not imply endorsement by the Bureau 

of Mines. 




as the average of the final 15 values obtained. V0 2 and V E 
values were obtained approximately every 30 s during the 
final 5 min of lifting using a Beckman metabolic measure- 
ment cart. The data were averaged by the number of values 
acquired during this 5-min period. 

During the tests of lifting capacity, integrated elec- 
tromyography (EMG) was obtained from the same eight 
trunk muscles in five of the subjects. The muscles studied 
were the right and left erector spinae, latissimus dorsi, ex- 
ternal oblique, and rectus abdominis (see figure 2). These 
data were obtained during the first and last minutes of the 
lifting period. The purpose of this data collection was to ex- 
amine the function of trunk muscles during lifting in 
stooped and kneeling postures. The integrated EMG data 
were analyzed as a percentage of the maximum EMG ac- 
tivity for each specific muscle. 

The results of data for the tests of lifting capacity in 
kneeling and stooped postures (along with the associated 
metabolic demands) were analyzed using Student's t-test. 
Integrated EMG data obtained during the tests of lifting 
capacity were analyzed using a 2 by 2 by 3 (posture X 
beginning-ending of lifting period X initial box weight) 
analysis of variance (ANOVA). Critical alpha levels were 
0.05 in all cases. 



Left 
erector spinae 



Left ^\7 
latissimus dorsi \ I 



Right 
rectus abdominis 



Right 
external oblique 




Right 
erector spinae 



Right 
latissimus dorsi 



Left 
rectus abdominis 



Left 
external oblique 



Figure 1.— Schematic of subject performing lifting capacity 
test in stooped posture. 



Figure 2.— Trunk muscles studied by means of electro- 
myography. 



23 



RESULTS 

The results of the psychophysical^ determined MAWL 
tests are presented in table 1. As demonstrated in this table, 
the kneeling MAWL for the 11 subjects was significantly 
lower than the stooped MAWL [probability (p) <0.01]. 
However, despite the fact that significantly less weight was 
lifted in this posture, the physiological demands of lifting 
in this posture were significantly higher than the stooped 
posture for HR (p <0.01) and V E (p <0.05). 

Table 1.— Results of maximum acceptable weight of lift 
(MAWL) test for all underground miners (N = 11) 

Stooped Kneeling p, prob- 

Rate SD Rate SD ability 

MAWL lb.. 66.2 ±9^5 58.5 ±11.7 <0.01 

Heart rate (HR) beats/min. . 122 ±12 136 ±14 <.01 

Oxygen utilization 

(V0 2 ) (mL/kg)/min . . 14.6 ±3.0 16.0 ±4.5 '.057 

Ventilation volume (V £ ) ... L/min . . 31.6 ±4.8 34.7 ±8.0 <.05 
Respiratory exchange ratio (R) .. . .82 ±.09 .83 ±.07 1 .843 

SD Standard deviation. ' Not significant. 

The data for determining the metabolic cost of lifting 
a 50-lb box are presented in table 2. The data presented in 
this table clearly demonstrate the greater metabolic 
demands of lifting in the kneeling posture. HR (p <0.001), 
V0 2 (p <0.001), V E ip <0.001), and respiratory exchange ratio 
(R) {p <0.05) were all significantly greater in the kneeling 
posture compared to the stooped position. 

Table 2.— Metabolic cost of lifting a 50-lb box for 
underground miners (N = 1l) 



Stooped 



Kneeling 



Rate SD Rate SD 



p, prob- 
ability 



Heart rate (HR) beats/min. . 116 ±11 129 ±16 <0.01 

Oxygen utilization 

V0 2 ) (mL/kg)/min . . 12.6 ±2.7 14.9 ±2.7 <.001 

Ventilation volume (V £ ) ... L/min . . 25.5 ±5.5 30.9 ±5.9 <.001 

Respiratory exchange ratio (R) . . . .79 ±.08 .82 ±.09 <.05 

SD Standard deviation. 

The four back muscles studied demonstrated signifi- 
cantly more integrated EMG activity in the kneeling 
posture as opposed to lifting while stooped. The ANOVA 
(using Fisher's statistic, F) for mean integrated EMG show- 
ed significant main effects due to posture for the right 
latissimus dorsi (F = 37.889, p <0.001), left latissimus dorsi 
(F = 8.189, p <0.01), right erector spinae (F = 30.522, p 
<0.001), and left erector spinae (F = 6.736, p< 0.05). 
Similarly, the ANOVA for maximum integrated EMG 
demonstrated significant main effects due to posture for the 
right latissimus dorsi (F = 56.549, p <0.001), left latissimus 
dorsi (F = 11.739, p <0.01), right erector spinae (F = 35.992, 
p <0.001), and left erector spinae (F = 26.673, p <0.001). 

Table 3 shows the average values (for five subjects) of 
the maximum integrated EMG for all four back muscles 
during lifting in both stooped and kneeling postures. 

Table 3.— Percentage of maximum electromyography (EMG) 
during lifting tasks in stooped and kneeling postures 

(N = 5) 

p, prob- 
ability 



Stooped 



Kneeling 



Latissimus dorsi: 

Right 

Left 

Erector spinae: 

Right 

Left 



24 
23 

13 
16 



71 
53 



53 
52 



<0.001 
<.005 

<.001 
<.001 



Similar results were obtained in the analysis of mean in- 
tegrated EMG. None of the abdominal muscles studied (i.e., 
left and right external obliques and rectus abdominus) were 
significantly affected by posture (p >0.05). There were no 
significant effects on any muscle due to, initial box weight 
(p >0.05) or due to sampling the EMG's at the beginning 
or the end of the lifting period (p >0.05). Furthermore, there 
were no signficant interactions observed between any of the 
independent variables {p >0.05). 

EFFECTS OF POSTURE ON LIFTING CAPACITY 

Results of the psychophysical tests of lifting capacity 
demonstrated that the lifting capacity of underground 
miners is significantly lower in the kneeling posture than 
in the stooped position. This difference is due primarily to 
the decrease in muscle mass that can be utilized when lif- 
ting in the kneeling position. These results indicate that 
there is a significant biomechanical disadvantage to lifting 
in the kneeling position as compared to the stooped-over 
posture. It should be noted that this biomechanical handicap 
(i.e., decreased muscle mass) was also evident in the back 
strength investigation reported below. 

The results of analyses of integrated EMG data collected 
during the lifting capacity sessions indicate that the loading 
on the back due to contraction of the back muscles is also 
quite different in these two restricted work postures. All 
four back muscles studied (i.e., right and left erector spinae 
and latissimus dorsi) demonstrated significantly higher 
muscular activity when subjects were lifting in the kneel- 
ing posture. 

The greater the contraction of the back muscles, the 
greater the compressive load that is experienced by the in- 
tervertebral (rV) disks of the spinal column. Therefore, an 
increased load is experienced by the IV disks and other 
structures of the vertebral column when lifting is per- 
formed in the kneeling posture. This will ultimately lead 
to increased wear and tear on these structures, which may 
lead to an increased incidence of back pain. Furthermore, 
these results indicate that the back muscles are working 
at a high intensity of a reduced muscular capacity when 
lifting in the kneeling posture. This would indicate that the 
back muscles will fatigue more quickly when performing 
materials-handling tasks in the kneeling posture. More 
rapid fatigue of the musculature of the back is another 
potential factor that may predispose the worker to experien- 
cing a back injury. 

It is interesting to note that physiological responses to 
lifting in the kneeling posture were significantly greater 
than in the stooped posture, despite the fact that less weight 
was lifted when kneeling. The increased metabolic demands 
of lifting in this posture is another factor that may limit 
lifting capacity in the kneeling position. One reason for the 
increased metabolic demands of lifting in this posture is the 
increased back muscle activity described earlier. An in- 
crease in muscular contraction increases the demand for 
oxygen in the working muscle, which in turn increases both 
heart rate and respiration in order to supply the necessary 
oxygen. The increased metabolic cost of lifting when kneel- 
ing is another indication that onset of fatigue will be more 
rapid when working in this posture. It should be borne in 
mind that physical fatigue also has psychological conse- 
quences that often lead to unsafe work practices, which may 
lead to an increase in musculoskeletal injuries. 

Previous research has indicated that an acceptable 
weight of lift be defined as one that can be lifted by 90 pet 



24 



of an industrial population, as determined in a 
psychophysical study. Establishing an acceptable weight- 
lifting burden according to this criterion has been shown 
to significantly reduce the cost and incidence of low-back 
pain. 

Based on the data on lifting capacity of underground 
miners in the stooped and kneeling postures presented in 
this paper, the acceptable weight of lift for the stooped 
posture is 54.0 lb, while the acceptable weight of lift for the 
kneeling posture is 43.5 lb. These values are based on a lift- 
ing frequency of 10 lifts/min and apply to lifting compact 
loads. This result is of some interest because of the fact that 
one of the most commonly handled materials in 
underground coal mines is the 50-lb rock-dust bag. 



Based on the acceptable weight-lifting burdens de- 
scribed, 50 lb is an acceptable weight of lift for the stooped 
posture; however, it exceeds the recommended maximum 
for lifting in the kneeling posture. This outcome suggests 
that redesign of certain materials should be given serious 
consideration. For instance, rock dust might be packaged 
in 40-lb instead of 50-lb bags in order to conform to the ac- 
ceptable weight-lifting burden recommended for the kneel- 
ing posture, especially in mines where a great deal of lift- 
ing is performed in this posture. Redesign of other com- 
monly handled supplies should also be examined. Such 
ergonomic redesign of supplies may have a significant im- 
pact on the costs associated with back injuries in low-coal 
mines. 



BACK STRENGTH OF UNDERGROUND MINERS 
IN STANDING AND KNEELING POSTURES 



METHOD 

Twelve coal miner subjects (M = 37 yr, ±8 yr SD) par- 
ticipated in tests of back strength in both standing and 
kneeling postures. Back strength was measured using a 
CYBEX Isokinetic Dynamometer (LUMEX, Inc.). A total 
of 12 conditions were studied in this experiment: six kneel- 
ing and six standing. In each posture, three back strength 
measurements were taken using an isometric contrac- 
tion (22.5 °, 45.0°, and 67.5 ° from vertical) and three meas- 
urements were made using a dynamic contraction (30%, 



60 7s, and 90 7s). Figure 3 is a schematic of the device used 
to measure back strength during tests in both standing and 
kneeling postures. The subject was secured by a pelvic 
stabilization strap in each posture. All back strength test 
conditions were conducted in a counterbalanced order. 

The maximum voluntary contraction (MVC) for each 
test condition was obtained using a test-retest procedure 
whereby peak torque measurements (foot-pounds) of two 
maximal exertions were required to be within 10 pet of one 
another (1 1 ). The higher of these two values was taken as 
the MVC for that test condition. Two minutes rest was given 





Figure 3.— Schematic of subject performing back strength exertions in (A) standing, and (B) kneeling postures. 



25 



between exertions, and consistent verbal encouragement 
was given in order to facilitate maximal exertions from the 
participants. 

During the back strength exertions, integrated EMG 
data were collected from eight trunk muscles in five of the 
subjects studied. The muscles studied were both right and 
left erector spinae, latissimums dorsi, external obliques, and 
rectus abdominis. Resting EMG values for all eight muscles 
were obtained in both postures (standing and kneeling) at 
three trunk angles; 22.5°, 45.0°, 67.5° from vertical. The 
EMG data for each exertion were expressed as a percen- 
tage of the maximum integrated EMG obtained over all 
tests for each specific muscle. 

The data collected on peak torque achieved during the 
static back strength tests were analyzed in a 2 by 3 (posture 
X trunk angle) ANOVA on repeated measures design. Data 
for the dynamic strength tests were also analyzed in a 2 
by 3 (posture X speed of contraction) ANOVA on repeated 
measures design. The integrated EMG data of each trunk 
muscle obtained during the back strength testing was 
analyzed using a 2 by 3 by 4 (posture X trunk angle X velo- 
city) ANOVA. The level of significance was 0.05 in all cases. 



RESULTS 

Posture did not significantly affect peak torque for either 
static back strength (F 14 = 2.186, p = 0.213) or dynamic 
back strength (F 1>4 = 0.535, p = 0.505). Trunk angle 
demonstrated a significant main effect on peak torque pro- 
duction for the static exertions (F 2a = 11.337, p <0.05). 
However, speed of contraction did not demonstrate 
significance for the dynamic back strength tests (F 28 = 
1.35, p = 0.310). Neither the interaction between posture 
and trunk angle in the static exertions (F 2 (8 = 1.295, p = 
0.319), nor the interaction of posture and speed of contrac- 
tion in the dynamic test (F 2S = 0.967, p = 0.381) were 
significant. 

The back strength data are presented in figure 4. The 
analysis of the static back strength of the 12 subjects 
demonstrated a significant main effect on peak torque due 
to trunk angle (F 222 = 34.797, p <0. 001); however, posture 
did not significantly affect peak torque production in the 
static exertions (F M , = 3.414, p = 0.092). 

Posture did have a significant main effect on peak 
torque produced in the dynamic exertions (F ltl = 8.797, 
p <0.05), as did the speed of the dynamic contraction (F 222 
= 13.469, p <0.001). The interaction between variables was 
not significant in either the static exertions, (F 2 22 = 0.326, 
p = 0.725), or the dynamic exertions (F 2 22 = 0.042, p = 
0.959). 

Tables 4 and 5 present summaries of the ANOVA 
results for maximum and mean EMG data collected dur- 
ing the back strength exertions, respectively. Posture was 
found to affect only the EMG activity of the left latissimus 
dorsi muscle, which was higher in the kneeling posture than 
the standing posture. However, it should be noted that all 
four back muscles studied had generally greater EMG ac- 
tivity in the kneeling posture than when standing. The 
failure of this trend to achieve statistical significance is 
probably the result of the limited EMG sample size. In the 
analysis of both maximum and mean integrated EMG ac- 
tivity, the latissimus dorsi muscles were more affected by 
the velocity of contraction, while the erector spinae muscles 
were more significantly affected by the angle of trunk flex- 
ion during tbe back strength exertion. 



KEY 
■i Standing 
EZ3 Kneeling 




.a 80 



22.5 45 67.5 

TRUNK ANGLE, deg 




30 60 

VELOCITY deg/s 

Figure 4.— Peak torque achieved by underground miners dur- 
ing (A) static, and (B) dynamic back strength tests. 

Figure 5 presents averaged data describing the relative 
myoelectric activity of the erector spinae and latissimus 
dorsi muscles and the relative torque achieved, expressed 
as a function of velocity of contraction. This figure 
demonstrates that while the function of the back muscles 
studied are similar in static exertions whether standing or 
kneeling, that there are significant differences in trunk 
muscle function in the dynamic contractions. For instance, 
while the relative activity of the latissimus dorsi declines 
consistently in the standing exertions as the speed of con- 
traction increases, in the kneeling posture one can see an 
increase in latissimus activity at the faster speeds. Further- 
more, the erector spinae muscles exhibit a dramatic increase 



26 



Table 4.— Summary of ANOVA results for maximum 

integrated electromyography (EMG) and torque during 

experimental conditions, probability (p) 



Posture 



Trunk 
angle 



Velocity 



Latissimus dorsi: 

Right 

Left 

Erector spinae: 

Right 

Left 

External oblique: 

Right 

Left 

Rectus abdominis: 

Right 

Left 

Normalized torque 



0.20 
<.05 

.08 

.11 

.36 
.06 

.73 
.26 
.25 



0.19 
.40 

-C.001 
<.001 

.09 
.10 

.49 

.36 

<.001 



<0.001 
<.001 

.36 
.41 

<.05 
.13 

.64 

.93 

<.001 



Table 5.— Summary of ANOVA results for mean 

integrated electromyography (EMG) and torque during 

experimental conditions, probability (p) 



Posture 



Trunk 
angle 



Velocity 



Latissimus dorsi: 
Right 


0.21 
<.05 

.16 
.13 

.32 

.14 

.65 
.26 
.20 


<0.01 
<.05 

<.001 
<.001 

<.01 
<.001 

.12 
<.05 
<.001 


<0.05 


Left 

Erector spinae: 

Right 


<.05 

.07 


Left 

External oblique: 
Right 


.27 
.54 


Left 

Rectus abdominis: 

Right 

Left 

Normalized torque . . 


.59 

.83 

.98 

<.001 




O 30 60 90 

VELOCITY, deg/s 

Figure 5.— Mean latissimus dorsi (Lat.) and erector spinae 
(Erec.) EMG, and torque production (percent of maximum tor- 
que achieved) averaged over experimental angles and express- 
ed as a function of velocity in (A) standing and (B) kneeling back 
exertions. 



in activity between the static condition and the 307s con- 
traction when kneeling; this sudden increase in activity is 
not seen in the standing posture. However, despite the 
higher EMG acitivity of the back muscles in the kneeling 
posture, it can be seen that decrease in relative torque as 
a function of increasing speed of contraction is greater in 
this posture than standing. 



EFFECTS OF POSTURE ON BACK STRENGTH 

Results of the back strength testing of 12 subjects in- 
dicate that there is a significant reduction in dynamic peak 
torque production when back strength is measured in the 
kneeling posture as opposed to standing. Static back 
strength was also generally lower in the kneeling position; 
however, the difference did not achieve statistical 
significance. The failure to achieve statistical significance 
of posture effects in the static tests is probably due to the 
limited sample tested thus far. 

Nevertheless, it should be noted that lifting tasks in 
underground mines (as in most industrial situations) are 
primarily performed dynamically, and the fact that 
underground miners exhibited less dynamic strength when 
kneeling indicates that miners who must lift in this posture 
are stressing their back musculature to a greater percen- 
tage of the muscles' total capacity than if the same lifting 
task were performed standing. Furthermore, as back 
strength correlates well with lifting capacity, a lower lift- 
ing capacity would be expected when handling materials 
in the kneeling position. This finding helps to explain the 
decreased lifting capacity of underground miners in the 
kneeling posture as described previously. 

Both trunk angle and velocity of contraction were 
demonstrated to have significant main effects on peak 
torque achieved during static and dynamic back strength 
exertions, respectively. These findings are in agreement 
with the results of previous studies that have examined the 
effects of these variables on back strength (12-13). The im- 
plication of this finding in the current investigation is to 
demonstrate that, although a decrease in torque is at- 
tributable to measurement of back strength in the kneel- 
ing posture, both trunk angle and velocity of contraction 
affect peak torque achieved in a similar manner, whether 
standing or kneeling. 

Both mean and maximum integrated EMG data were 
collected from five of the subjects who performed the back 
strength tests. The results of the analysis of both mean and 
maximum EMG's indicate that posture significantly af- 
fected only the activity of the left latissimus dorsi muscle, 
which was more active in the kneeling posture than when 
standing. However, it should be duly mentioned that all four 
back muscles examined were consistently more active in 
the kneeling posture than when standing. The failure to 
achieve statistical significance of back muscle function 
because of posture is probably a result of the limited EMG 
sample examined. 

Other findings from the back strength EMG analysis 
demonstrated that the erector spinae function was 
significantly more affected by the angle of the trunk dur- 
ing the exertion, while the latissimus dorsi muscles were 
affected more by the velocity of the contraction. These find- 
ings are in agreement with results from other researchers, 
and demonstrate that the effects of trunk angle and velo- 
city of contraction on back muscle function are not affected 
by the posture assumed during the exertion. 






27 



The results described reflect some of the effects that 
body posture has on the biomechanics of the muscle groups 
that may take part in a lifting activity. It is apparent that 
there is a reduced muscle mass employed during back ex- 
ertions in the kneeling posture as opposed to standing. This 
indicates that during the measurement of back strength in 
the standing posture, there is a contribution of muscular 
forces from muscles other than those of the low-back region, 
presumably the muscles of the posterior aspect of the legs. 

The implication of this finding is that, in order to truly 
determine the function of the low-back muscles, one must 
adequately isolate this muscle group. Differences in back 
strength measurements taken in the standing posture, in 
other words, may not accurately reflect true differences in 



force production of the low-back musculature, but may in- 
stead reflect differences in the strength of, say, the ham- 
string group. This is not to say that measurement of back 
strength in the standing position is not valuable; in most 
lifting situations, a worker will be able to use the additional 
muscular force afforded by the legs. However, if one assumes 
that standing measurements of back strength are indicative 
solely offerees produced by the low-back muscles, incorrect 
conclusions may be drawn. 

The author does not contend that the assessment of back 
strength in the kneeling posture affords the best method 
of isolating forces of low-back muscles. Further research is 
necessary before the optimal method of assessing low-back 
strength is identified. 



LABORATORY ASSESSMENT OF METABOLIC DEMANDS ASSOCIATED 
WITH SELECTED UNDERGROUND MATERIALS-HANDLING TASKS 



Increased metabolic demand is an indication that the 
onset of physical fatigue will be more rapid. Because 
physical fatigue has psychological consequences that often 
lead to unsafe work practices and associated 
musculoskeletal injuries, laboratory assessments of 
metabolic demands of three materials-handling tasks were 
made. 

METHOD 

Nine experienced low-seam coal miners were used as 
test subjects. Each subject performed three materials- 
handling tasks (i.e., crib building, brattice building, and 
moving rock-dust bags). In an attempt to replicate the con- 



ditions in the mine as closely as possible, an adjustable- 
height mine simulator was constructed and used for testing. 
The simulator was constructed of sections of 2- by 4-in fram- 
ing that bolted together to provide a 12- by 16-ft cage with 
a roof that could be varied in height (see figures 6-8). The 
miners were instructed to complete the following tasks. 
Crib Building.— The crib building task involved having 
the miner move the necessary crib blocks (rough-sawn 6- 
by 6-in blocks, approximately 3.5 ft long, weighing approx- 
imately 14-16 lb) from one side of the simulator to the other 
and then proceed with building the crib. The blocks were 
placed in tiers in alternating directions until the necessary 
height was reached and then tightening wedges were in- 
serted to complete the task. 




Figure 6.— Underground mining test subject building a roof-support cribbing during which metabolic data are gathered (note 
mouthpiece, headgear, and flexibile tubing for collection of expired gases). 



28 




Figure 7.— Test subject building a brattice (ventilation stopping). 




Figure 8.— Miner lifting 50-lb rock-dust bags from a supply pile to the opposite side of the mine simulator. 



29 



Brattice Building.— The requirements for this task were 
to move the necessary number of standard cinder blocks (ap- 
proximately 22 lb each) from one side of the simulator to 
the other and to build a stopping five blocks high. Each 
miner used the approach of moving several blocks, building, 
and repeating the process until the task was completed. 

Moving Rock-Dust Bags.— This task was designed to 
simulate removing a load of rock-dust bags from a scoop. 
It involved moving 22 standard (50-lb) rock-dust bags from 
a pile on one side of the simulator to a pile on the other 
side. Each bag was moved between 6 and 8 ft. 

Each miner was outfitted with a welder-type headset, 
one-way respiratory valve, mouthpiece, and nose clip (see 
figures 6-8). The expiratory side of the respiratory valve 
was attached to a Beckman metabolic measurement cart 
via a flexible respiratory tubing. This flexible tubing was 
necessary to allow the subjects to perform the specified task 
and have the measurement cart located outside of the 
simulator. The cart was calibrated for volume, 2 , and C0 2 
prior to each testing session. The cart produced printouts 
at 30-s intervals for (a) volume expired, (b) V0 2 in L/min 
and (mL/kg)/min, and (c) respiratory exchange ratios. 

The preparatory phase for each session involved fitting 
the subject with the headgear and respiratory valves, and 
allowing the subject to rest in a kneeling position in the 
simulator until reasonable baseline values (V0 2 <0.50 
L/min) were being recorded. The subject then performed the 
task while data were recorded continuously. The duration 
of the tasks was such that five to eight metabolic recordings 
were made during the work period. Recovery samples were 
recorded continuously from the end of the task until the 
subjects were back to near baseline values (V0 2 = 0.50 
L/min). The recovery phase typically lasted 3 to 5 min. 



RESULTS AND DISCUSSION 

The metabolic data clearly indicate that moving rock- 
dust bags was the most physiologically demanding of the 
materials-handling tasks evaluated. Figure 9 presents a 
comparison of the oxygen uptake, in liters per minute, for 



.E 2.5 

E 

_i 

X- 2.2 

I- 
o_ 

<f) 

o 
o 



1.0 



.5 



LlI 
CD 
> 
X 

o 



Rest 



Work 



Recovery 




KEY 
Building crib 
a Building brattice 
• Move rock dust 

_L_ ! L_ 




5 10 

OBSERVATION NUMBER 



15 



all three tasks. Inspection of this figure reveals a much 
greater rate of rise of oxygen uptake for moving rock-dust 
bags as compared with oxygen uptake for the other tasks. 
The increased slope is an additional indication of the sever- 
ity of the task. The metabolic demands of cribbing (5.20 
METS 4 ) and building a ventilation stopping (4.95 METS) 
were quite similar and notably lower than the maximum 
recorded value of 6.25 METS for moving rock-dust bags. 

The data presented in this paper are very comprable to 
results obtained by Ayoub (14), who measured the metabolic 
demands of miners performing various jobs in a low -seam 
underground mine. The tasks studied in that research were 
typically of a relatively short-duration (3 to 5 min in length), 
and required oxygen uptake values ranging from approx- 
imately 1.00 L/min (for roof bolting) to roughtly 2.25 L/min 
(for setting jacks, bending bolts, and moving materials). 
Other metabolic demands for mining tasks reported by 
Ayoub included shoveling (1.86 L/min), helping (1.45 L/min), 
and timbering (1.20 L/min). In comparison with the data 
from Ayoub (14), the data for building a crib or a stopping 
presented in this paper might be considered average in 
terms of energy expenditure for mining jobs, while moving 
rock-dust bags would require a greater than average 
metabolic cost as compared to most mining tasks. 

As noted, the most difficult task identified in the 
laboratory assessment was that of moving rock-dust bags. 
From a physiological standpoint, consideration should be 
given to redesigning this task. Three possible approaches 
might be considered: (a) the weight of the individual bags 
could be reduced from the present 50 lb to 40 lb; (b) a train- 
ing program could be developed to reduce the rate at which 
the present 50-lb bags are handled; and (c) methods of 
delivering rock dust mechanically should be investigated. 
If none of these alternatives are viable, an effort should be 
made to introduce frequent rest pauses during the 
unloading of bags of rock dust. 

The crib and brattice building tasks were less 
physiologically demanding than moving rock dust. It is im- 
portant to note, however, that the intensity required to do 
either of these "easier" tasks could not be sustained for a 
major segment of a workday. Fortunately, the sporadic 
nature of materials-handling tasks in underground mines 
does not require that any of these tasks be performed for 
extended periods of time. 

RECOMMENDED WORK-REST INTERVALS FOR 
MINING TASKS 

Knowledge of the energy expenditure necessary for 
specific mining tasks is valuable in calculating recom- 
mended work-rest intervals that should be followed in order 
to prevent excessive muscular fatigue. The American In- 
dustrial Hygiene Association (16) endorses the following 
formula in establishing work-rest cycles: 

RT pet = [(W - 1.5/4) - 1] x 100, 



where RT pet 
and W 



rest time as a percentage of the time 
of work, 

energy expenditure during work in 
terms of kilocalories expended per 
minute. 



Figure 9.— Comparison of oxygen consumption rates during 
performance of three materials-handling tasks. 



4 MET (metabolic equivalent) is the amount of oxygen required per minute 
by the body under resting conditions. It is equal to 3.5 mL of oxygen con- 
sumed per kilogram body weight per minute. 



30 



Because an oxygen consumption rate of 1 L/min is 
equivalent to 5.05 kcal expended per minute, the data 
presented in this section can be used to calculate the work- 
rest intervals. For moving rock-dust bags (at a frequency 
of 12 to 15 per minute) the recommended rest interval would 
be 120 pet of the time of work. This would mean that if rock- 
dust bags were moved at a rate of 12 to 15 per minute for 
a 5-min period of time, the worker should take a 6-min rest 
break in order for the muscles to recover from the activity. 
This rest break would allow heart rate and breathing to 
return to normal, as well as allowing the metabolic end- 
products of muscular exertion (that lead to muscular 
fatigue) to be dissipated. Crib building would require a rest 
break equivalent to 75 pet of the time of work according 
to the American Industrial Hygiene Association formula, 
and building a ventilation stopping would require a rest 



break equivalent to 70 pet of the time of work. These results 
and the results of studies of energy expenditures during 
mining tasks from previous authors provide the basis for 
work-rest intervals shown in table 6. 



Table 6.— Recommended work-rest intervals for several 
underground mining tasks 





Energy expendi- 
ture, kcal/min 


Rest interval, 
pet of work time 


Moving rock dust bags 
(12-15 bags/min) 

Shoveling 

Building a crib 

Building a stopping .... 

Helping (miner helper 
and root bolt helper . . . 

Timbering 


10.25 
9.28 
8.48 
8.28 

7.15 
6.00 


120 
95 
75 
70 

41 
13 



PRELIMINARY RECOMMENDATIONS FOR LIFTING IN LOW-SEAM MINES 



TRADITIONAL LIFTING RECOMMENDATIONS 

The following traditional lifting recommendations are 
provided for performance of materials-handling tasks in low- 
seam coal mines. 

1. Use a mechanical assist whenever possible.— It is ob- 
vious that elimination of a manual lifting task by using a 
mechnical device is the preferred method of handling 
materials, and that eliminating the lifting task will reduce 
the number of back injuries due to materials handling. The 
development of new materials-handling devices is certainly 
a need in low-coal mines, and mining personnel (both the 
miners and mine management) should be encouraged to 
think of ways that physically demanding jobs might be 
redesigned by using a mechanical-assist device. 

2. Implement systems approach to supplies handling.— 
Supply-handling systems in underground coal mines should 
be analyzed in order to reduce the number of times that 
materials are handled. For instance, it has been 
demonstrated that it is possible to keep materials unitized 
on pallets until the supplies reach an underground storage 
location, thereby eliminating all manual handling of 
materials up to this point. However, many mines do not use 
such a system; instead, palletized loads are broken on the 
surface and the materials are then loaded manually onto 
supply cars. Every effort should be made to keep supplies 
palletized until they absolutely must be used on an in- 
dividual basis. 

3. Use a smooth lifting motion to accomplish a lift.— A 
great deal of research has indicated that sudden or unex- 
pected movements are responsible for a large number of 
back injuries. The sudden load experienced by a worker's 
back in this situation is often two to three times as great 
as when the load is expected. Related to this concept is the 
recommendation that if an object is stuck underneath other 
materials, do not attempt to lift it without first removing 
the debris on top of it. Two problems can be caused by at- 
tempting to lift a stuck object. First, the object may not move 
when expected to, which causes a very high load to be ex- 
perienced by the lower back; secondly, the object may pull 
free unexpectedly, which will also place the low back under 
extremely high stress. 

4. Keep the load as close to the body as possible.— 
Biomechanical studies on the loading of the low back have 
made it clear that the further the load is from the spine, 



the greater the stress to the low back. Therefore, it is im- 
portant to keep the load close. While the stooped posture 
limits how close the load can be from the body, it is still 
much better to handle the material with the arms hanging 
straight down than having to extend them out in front of 
the body when handling a load in the stooped position. 

5. Avoid excessive twisting of the trunk.— Many re- 
searchers are of the opinion that the worst action to per- 
form when lifting is twisting. Twisting puts a severe strain 
on the fibers of the intervertebral disk, and may actually 
cause some of these fibers to break, which will severely 
weaken the disk. Furthermore, it is the opinion of some 
researchers that injuries to the disk that are caused by 
twisting are much less likely to heal than injuries to the 
disk caused by simple bending. Therefore, it is important 
to position the body so that a minimum of twisting is re- 
quired to perform a lifting task. 

6. If an object is too heavy to lift by yourself, get help.— 
Many back injuries occur because of a person trying to lift 
more weight than one individual can safely lift. It is im- 
portant to take the time to find someone to assist with the 
lifting task. 

7. Become more physically fit. —Being a miner is one of 
the most physically demanding jobs imaginable. This means 
that miners should be more fit than most other workers in 
order to meet the physical requirements of the job. Un- 
fortunately, many studies have shown just the opposite to 
be the case. Many back injuries could probably be avoided 
by strengthening back and abdominal muscles and mak- 
ing them more flexible. 

8. Take care of your back at home. —Attention to back 
care should not stop at the portal. Many back injuries may 
be caused by everyday activities such as driving with the 
seat of your car too far back, doing yard work, or sleeping 
on a mattress that is too soft. There are also two-person jobs 
at home, and it is important that the safe lifting techniques 
employed at work be transferred to the home environment. 



RECOMMENDATIONS BASED ON BUREAU 
ERGONOMICS LABORATORY RESEARCH 

The studies described in this paper have been performed 
by the Bureau to determine the specific lifting stresses en- 
countered by low-coal miners. These studies have included 



31 



tests of psychophysically determined lifting capacity, assess- 
ment of the back strength of the underground mining 
population, the relationship of back strength to lifting 
capacity in restricted work postures, and the metabolic 
demands of materials-handling tasks in kneeling and 
stooped postures. It should be noted that the following 
recommendations deal primarily with compact loads (such 
as rock-dust bags, cribbing block, and concrete blocks) that 
are handled repetitively by underground miners. Future 
research will focus on other aspects of underground 
materials handling. It should be recognized that the sam- 
ple size on which these recommendations are based is still 
somewhat limited. However, many statistically significant 
findings have already been demonstrated through in-house 
Bureau research with regard to acceptable weights of lift 
in restricted work postures and the physiological costs of 
lifting activities in these postures. The following recom- 
mendations are based upon the results of this research. 

1. Maximum acceptable weights oflift(MAWL) for kneel- 
ing and stooped postures.— The results of the psychophysical 
tests of lifting capacity of underground coal miners have 
demonstrated that the acceptable weight of lift in the kneel- 
ing posture is significantly lower than that of the stooped 
posture (p <0.01). It has been shown that an acceptable 
weight of lift is defined as one that 90 pet of the working 
population are able to lift using the psychophysical 
methodology (15). Using this criterion, the MAWL's for 
underground miners are 54.0 lb in the stooped posture, and 
43.5 lb in the kneeling posture. 

2. Heavier weights may be handled more safely in the 
stooped posture.— Given a choice of handling a heavy weight 
(> 50 lb) in the stooped or kneeling positions, it may be bet- 
ter to handle the weight stooped, because of the higher lift- 
ing capacity of miners in this posture. The results of the 
research indicate that the stooped posture may be better, 
though admittedly not a great deal better, for handling 
heavier loads as compared to the kneeling posture. 

3. More frequent rest breaks should be taken in the kneel- 
ing posture.— The studies performed at the Bureau's 
ergonomics laboratory have clearly indicated that increas- 
ed metabolic demands are required when handling 
materials in the kneeling posture. In fact, the underground 
miners tested to date have demonstrated that both heart 
rate and ventilation volume have been significantly higher 
in the kneeling posture than stooped (p <0.05), despite the 
fact that significantly less weight was lifted when kneel- 
ing (p <0.01). Therefore, in order to prevent the onset of 
muscular fatigue that may ultimately lead to 
musculoskeletal injury, more frequent rest breaks may be 
necessary in the kneeling posture. 

4. Redesign of manually handled materials used in low- 
coal mines should be considered.— Bureau research has in- 



dicated that in low-coal mines, nearly 60 pet of a worker's 
time spent in materials-handling activities may be in the 
kneeling posture (1). Because of the lower lifting capacity 
of miners in this position, consideration should be given to 
redesign of the loads that must be handled in low-coal 
mines. For instance, a 50-lb rock-dust bag is an acceptable 
weight to lift in the stooped posture according to the find- 
ings reported. However, this weight is significantly higher 
than the acceptable weight of lift for the kneeling posture 
(i.e., 43.5 lb). Therefore, it may be advisable to consider 
repackaging rock dust into 40-lb bags for low-coal mines 
that require a great deal of materials handling in the kneel- 
ing position. Designing the load to match the 
psychophysically established acceptable weight of lift has 
been shown to be beneficial in decreasing both the incidence 
and severity of back injuries (15 ). 

5. Recommended work-rest cycles for various mining 
tasks. —Recommended work-rest intervals for various min- 
ing tasks are presented in table 6. These work-rest cycles 
are based on a formula endorsed by the American Industrial 
Hygiene Association (16). Information on the energy expen- 
diture for the mining tasks included in this table are bas- 
ed on data collected by the Bureau (14). 

6. Effects of posture on back strength.— The analysis of 
back strengths of miners showed that dynamically 
measured back strength was significantly lower when 
kneeling as opposed to standing. A biomechnical analysis 
performed by the Bureau (not described in this paper) 
demonstrated that trunk extension was the primary action 
used to accomplish several underground materials-handling 
tasks (17). Therefore, a great deal of stress is being put on 
the back extensor muscles during the performance of these 
tasks at a time when the muscles are at a significant 
biomechanical disadvantage. Reducing the weight of loads 
handled in the kneeling posture may help to ease the burden 
on the stressed back muscles and may help to reduce the 
incidence of back injuries in this posture. 

7. Sensitivity to working in the stooped posture.— It 
became apparent during the tests of lifting capacity that 
certain individuals were not as tolerant to working in the 
stooped posture as others. These individuals were generally 
those who had more incidence of low-back pain. Overweight 
test subjects also tended to be more sensitive to stooped 
materials handling. One subject elected not to finish the 
lifting capacity test in this posture. Therefore, it is sug- 
gested that individuals who have experienced significant 
low-back pain or who are overweight, exercise particular 
caution when handling materials while stooped. Shorter 
periods of materials handling in this procedure are indicated 
for such individuals in order to prevent recurrence of low- 
back pain. 



32 



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burgh, PA, August 9, 1983, and Reno, NV, August 15, 1983, comp. 
by J. M. Peay. BuMines IC 8948, 1983, pp. 54-63. 



11. Stobbe, T. J., and R. W. Plummer. A Test-Retest Criterion 
for Isometric Strength Testing. Paper in Proceedings of the Human 
Factors Society Annual Meeting (San Antonio, TX, October 22-26, 
1984), pp. 455-459. 

12. Marras, W. S., A. I. King, and R. L. Joynt. Measurements 
of Loads on the Lumbar Spine Under Isometric and Isokinetic Con- 
ditions. Spine, v. 9, No. 2, 1984, pp. 176-188. 

13. Smith, S. S., T. G. Mayer, R. J. Gatchel, and T. J. Becker. 
Quantification of Lumbar Function, Part 1: Isometric and 
Multispeed Isokinetic Trunk Strength Measures in Sagittal and 
Axial Planes in Normal Subjects. Spine, v. 10, No. 8, 1985, pp. 
757-772. 

14. Ayoub, M. M., N. J. Bethea, M. Bobo, C. L. Burford, D. K. 
Caddel, K. Intaranont, S. Morrissey, and J. L. Selan. Mining in 
Low Coal. Volume 1: Biomechanics and Work Physiology (Contract 
H0387022, TX Tech. Univ.). BuMines OFR 162(l)-83, 1981, 175 
pp.; NTIS PB 83-258160. 

15. Snook, S. H., and V. M. Ciriello. Maximum Weights and 
Workloads Acceptable to Female Workers. J. Occ. Med., v. 16, 1974, 
pp. 527-534. 

16. American Industrial Hygiene Association. Ergonomics Guide 
to Assessment of Metabolic and Cardiac Costs of Physical Work. 
Am. Ind. Hyg. Assoc. J., v. 32, No. 8, 1971, pp. 560-564. 

17. Shapiro, R., C. Blow, and J. T. Kearney. Biomechanical 
Evaluation of Simulated Materials-Handling Tasks in Low-Seam 
Coal Mining. Paper in Proceedings of the Collegiate Association 
for Mining Education (5th Annu. Meet., Beckley, WV, Oct. 2-3, 
1986), in press. 






33 



ERGONOMIC ANALYSIS OF THE JACKLEG DRILL 



By Thomas G. Bobick, 1 William S. Marras, 2 and Steven A. Lavender 3 



ABSTRACT 



Research conducted for the Bureau of Mines by The Ohio State University has in- 
dicated that the jackleg drill, commonly used in underground metal-nonmetal mines, 
was involved with 46 pet of all lost-time handtool-related accidents during the 1978-83 
6-yr period. Videotapes of underground operations of jackleg drills have been collected 
and analyzed to determine the drills' biomechanical forces on the operators. 

A detailed task analysis identified that carrying the drill, positioning the drill steel, 
collaring the hole, and pulling the drill steel out of downward angled holes all contribute 
severe loadings to the drill operator's lumbar spine. A laboratory experiment was de- 
signed to investigate the stresses on the trunk muscles while performing these four 
tasks under controlled conditions. Preliminary electromyographic (EMG) data are 
presented. 



INTRODUCTION 



Handtools have been in use by humans since prehistoric 
times. They are commonly found in most households and 
are regularly used in virtually all occupations. Certain in- 
dustries and occupations require workers to use handtools 
more often then others, and many times the nature of the 
task or tool puts these workers at a greater risk of injury 
than the typical industrial population. Underground min- 
ing is just such an industry. 

Statistics from the Mine Safety and Health Administra- 
tion (MSHA), Department of Labor, indicate that from 1980 
through 1984 handtools were involved in a total of 8 pet 
of all the lost-time nonfatal injuries in underground coal 
mining. 4 In addition, a total of 21 pet of all hand and finger 
injuries were caused by the use of handtools during the 
same 5-yr period. 5 

Mining is the brute-force extraction of raw materials 
from the surrounding rock. Thus, the extraction equipment 
is very large, quite powerful, and made to be durable. Hand- 
held powered tools, such as pneumatically powered drills, 
which are used to drill holes for the insertion of rock- 
securing bolts or for the insertion of explosives to blast the 
product from the seam, are made for very rough handling 
and have to be durable. In order to be durable, pneumatic 
drills are made of steel, which makes them very heavy. 



1 Mining engineer, Pittsburgh Research Center, Bureau of Mines, Pitts- 
burgh, PA. 

2 Associate professor, The Ohio State University, Columbus, OH. 

3 Research assistant, The Ohio State University. 

4 Marras, W. S., T. G. Bobick, S. A. Lavender, T. H. Rockwell, and R. L. 
Lundquist. Hand Tool Risks in U.S. Underground Coal Mining: 1978-1983. 
Accepted for publication in 1987, Journal of Safety Research. 

5 Quisenberry, S. Hand and Finger Injuries in the Coal Mining Industry: 
19801984. MSHA Tech. Rep. PC-7004, 1985, 10 pp. 



In the underground coal mining industry, hand-carried 
pneumatic drills are called stopers. Figure 1 shows this drill 
in operation. The stoper is used almost exclusively in a ver- 
tical orientation. Its primary function is to drill holes into 
the overhead rock after the coal has been removed so steel 
rods can be inserted to stabilize and secure the overlying 
rock. In the underground metal-nonmetal mining in- 
dustries, the hand-carried pneumatic drills are called 
jackleg drills. Figure 2 shows this drill in horizontal opera- 
tion. The jackleg drill is used in a variety of angles- 
overhead, horizontally, and downward. 

The jackleg drill is used to drill holes for explosives so 
the ore can be blasted from the seam, as well as drilling 
holes for rock-securing bolts. The jackleg is bigger, heavier, 
and more awkward to operate than the stoping drill (stoper) 
that is used in underground coal mines. 

Both drill types have a pneumatically operated feed leg, 
which is used to extend the drill body, and thus the drill 
steel and bit, into the rock as the holes are drilled 4 to 6 
ft deep in coal mines and 4 to 12 ft deep in metal-nonmetal 
mines. The weight of the jackleg drill can range from 105 
to 125 lb, depending on the length of its feed leg and 
whether the leg is made of steel or aluminum. The drill body 
is usually constructed of steel for durability. 

The coal mine stoping drill, which is lighter than a 
jackleg drill, is used primarily in an overhead fashion. The 
jackleg drill is used at angles overhead and below horizon- 
tal; thus, for safe operation, it must be controlled with more 
technique and brute strength than the stoper. Inexperienced 
drillers often struggle against the jackleg drill during its 
operation, and thus impose large forces on their backs and 
arms. 



34 




Figure 1.— The stoping drill is used mainly in a vertical orientation in underground coal mines. 




Figure 2.— The jackleg drill is used in a variety of angles in underground metal-nonmetal mines. 



35 



RISK ANALYSIS 



The MSHA data base was used to evaluate the risks of 
injuries related to the use of jackleg drills in the under- 
ground metal-nonmetal (MNM) mining industry during the 
1978-83 6-yr period. During these 6 yr, over 4,000 accidents 
were reported, which resulted in over 40,000 lost workdays. 
The lost-day risk associated with using the jackleg drill and 
six other major tool categories in underground MNM min- 
ing are presented in table 1. The six other categories are 
included for comparison purposes. 

This table indicates that the jackleg drill was involved 
with over 1,900 lost-time accidents. These accidents resulted 
in more than 18,000 total lost workdays. An average of 
slightly less than 10 workdays were lost for each jackleg 
drill accident. 

Figure 3 summarizes the sequence of injury components 
associated with jackleg drill accidents over the 6-yr period. 
Over 62 pet of the injuries were due to "struck-by" types 
of accidents. The body parts injured most often in the struck- 
by accidents were the arms (39 pet), legs (23 pet), and head 
(22 pet). Cuts were usually sustained by these body 
segments (76, 63, and 54 pet) and, generally, the accidents 
resulted in relatively few lost days (2.5, 5.7, and 0.75, respec- 
tively). Struck-by injuries that involved a broken bone oc- 
curred most often to the trunk (23 pet), the legs (20 pet), 
and the arms (15 pet). These injuries usually resulted in 
a large number of lost days (28.2, 41.6, and 15.2, 
respectively). 

"Caught" injuries were the next most likely type of ac- 
cident to occur when using jackleg drills. The arm was in- 
volved over 91 pet of the time. These injuries usually 



Table 1 .—Lost-time risk associated with hand tool use 
in metal-nonmetal mining, 1978-83 

Lost-time Total lost Av days lost Share of total 

Tool category accidents workdays per accident lost days, pet 

Jackleg drill 1,913 18,048 9.43 44.11 

Scaling bar 1 ,033 16,546 16.02 40.44 

Pry bar 397 2,663 6.69 6.51 

Hammer and/or axe 405 1 ,902 4,69 4.65 

Wrench 189 1,170 6.16 2.86 

Knife 162 304 1.87 .74 

Jack 61 283 4,64 .69 

Total or av 4,160 40.916 9J54 10Q.QQ 



resulted in a cut or a break. The resulting number of days 
lost were 5.6 and 7.7, respectively. This low number in- 
dicates that most of the injuries occurred to the hands and 
fingers. 

The third most frequent accident type involved "exer- 
tion injuries." These accidents resulted in a higher number 
of average days lost (11.5) compared to the struck-by (9.5) 
and caught (6.7) type injuries. The vast majority of the ex- 
ertion injuries involved the trunk (78.5 pet). Of these, 92 
pet involved a muscle tear. The data for this accident type 
suggest that musculoskeletal injuries to the back are quite 
common. In fact, the overall probability value for the trunk- 
tear-exertion sequence (7.74 pet) is the third largest value 
(of the 91 entries) behind the cut-arm-struck-by sequence 
(18.66 pet) and the cut-leg-struck-by sequence (9.15 pet). The 
sequence probability concept indicates that when a lost-time 
injury has occurred with a jackleg drill, a tearing injury 
to the trunk caused by a worker's overexertion is the third 
most likely event that will occur. 



DATA COLLECTION AND ANALYSIS 



MINE STUDY 

After the development of the tree-branching diagram 
(fig. 3), several mine visits were conducted to gather addi- 
tional data. During these visits, videotapes were collected 
of different miners operating jackleg drills. Additionally, 
the drill operators were interviewed regarding their tech- 
nique(s) of operating the drill. Pertinent environmental data 
of the mines visited were also collected in an effort to quan- 
tify any differences or similarities among them. 

Analysis of the videotapes was the primary means of 
determining the forces that were imposed on the miner 
when operating the jackleg drill. As the tapes were re- 
viewed, the body positions of each drill operator were 
documented. The procedure for using the jackleg drill was 
noted. Figure 4 presents a schematic of the usual procedure 
for using a jackleg drill. 

A detailed task analysis was conducted on each operator 
videotaped. The tasks that required heavy muscular effort 
on the part of the operator were identified. Body segment 
angles and the direction of the forces that were exerted 
while using the drill were documented. 

After the overall body posture and the position of the 
body segments were noted, these postures were further 
analyzed with a static strength model. This permitted an 
initial estimate of the loadings and the forces imposed on 
various body joints, such as the shoulder, elbow, hip, knee, 
and the L^-Sj intervertebral disk. These estimates were 



related to overall body anthropometry (height, weight, and 
estimate of body morphology). The resultant joint loadings 
were compared to the strength capabilities of the general 
population. In addition, the loading on the lower back (LvSj 
disk) was compared to the action limit and the maximum 
permissible limit recommended by the National Institute 
for Occupational Safety and Health. 

Along with the task analysis and the biomechanical 
evaluation, the narratives associated with selected accidents 
were reviewed. Although these narratives were only brief 
descriptions (two or three sentences) of the accident, they 
often permitted the main problem of that accident to be 
identified. 

Four main tasks were identified on the videotapes that 
involved heavy muscular effort. These included carrying 
the drill into the workplace, positioning the drill steel 
against the rock face, collaring the drill hole (just begin- 
ning to start a hole, perhaps only 1/2 in deep), and remov- 
ing the drill steel after the hole was completed. Drilling the 
hole was not included with these tasks because the actual 
drilling does not really involve any heavy muscular forces. 

From these extensive analyses, different hypotheses 
related to accident possibilities were developed, discussed, 
and evaluated. Hypotheses were developed for the four tasks 
that involved heavy muscular effort (carrying, positioning, 
collaring, and removal). 

In addition, the videotapes revealed that inserting the 
drill steel into the drill chuck had to be done with one hand 



36 



Arm: N-290, TDL'1,884, Mean-6,50, (0.9 1 2) 



Haad: H=3. TDL=59, Maan = 19.67, (0.009) 



C. U ghl : N'318.TDL.2,12«,M..n-6.69, (0.166) V L *« : N ° 12 ' TDL=96, Maan=8.0, (0.038) 



Eiartlon: N'205, TDL-2,360, MaanO 1.5 1,(0. 107IA 



Fall: N-152, TDL-1B07, Mean = l2 55. (0.079)/. 



IUNM) 
JlOHl drill 

Mi 1,8 1 3 
TOL'18.048 

M«in-» 434 



\Multlple: N=5, TDL'6, Maan=1.2, (0 016) 



^ Trunk: N=8, TDL'81. Mean=10.13, (0.025) 



Arm: N = 29. TDL*593. Mean»20.4S, (0.141)^ 



Lag: N'9, TDL=123. M»l» = 13.67, (0.044) 



Multiple): N=4. TOL'10, Mean=2.50, (0.020) 



_Neck: N»2, TOL'47, M«an=23.5, (0.010) 



\Trunk: N-161. T0L=1 f 587, Mean=9. 86, (0.785) 



Arm: N=47. TDL°22 1, Mean=4.7, (0.309) 



H«ad: N=6, TDL=9. Mean=1.5, (0.039) 



Lag: N--27. TDL'191, Mean=7.07, (0.178) 



\Trunk: N"61, T0L«1,164, Kean=19.0, (0.401) 



(Prot>.) 
(0.266), 



Mean 
7.69, 



Sq. dl 
592 1, 



(0.167), 



Sq pr 
0.0403 



Multiple: N-10, TDL=317, Maarp31.7, (0.066) y/ m 


: 6, 


(0.600), 


41.33, 


248.0. 


0.0031 


\j= 


2, 


(0.200), 


23.00, 


46.0, 


0X1010 


\Neck: M"1, TDL-5, Mean. 5.0. (0.007) t: 


1, 


(1.000), 


5.00, 


5.0. 


0.0005 



Figure 3.— Tree-branching diagram showing the sequence of injury components associated with jackleg drill accidents in under- 
ground metal -nonmetal mining for the 1978-83 period. 



37 



(Struck ag: N = 45, TDL=326, Mean=7.24, (0.024) i 



| Struck by: N=1,193, TDL=1 1,329, Mean=9.50, (0.624) 





KEY 




N 


Lost time accident! 


TDL 


Total days lost 




( ) 


Probability that 


this segment 




will occur 




Mean 


Av days lost 




Sq. dl. 


Total days lost 
injury sequence 


tor this 


Sq. pr 


Probability that 


this entire 




sequence will occur 


b 


Break 




c 


Cut 




m 


Multiple 




o 

t 
d 


Other 

Tear 

Dust in eye 







b: 


2, 


(0.080), 


41.00, 


82.0, 


0.0010 


Arm: N=2S, TDL=101, Mean = 404. (0.556) , 


/%: 


21. 


(0.840), 


0.71, 


14.9, 


0.0110 


1 V. 


\o: 


2, 


(0.080), 


2.00, 


4.0, 


0.0010 


Head: N=6, TDL = 42. Mean 7.0. (0.133) 


b: 


1, 


(0.167), 


1.00, 


1.0, 


0.0005 




*\c: 


5, 


(0.833). 


8.20, 


41.0, 


0.0026 


Leg: N=7, T0L=32, Mean=4.57, (0.156) 


c: 


3, 


(0.429), 


0.00, 


0.0, 


0.0016 




\t: 


4, 


(0.571), 


8.00, 


32.0, 


0.C02 1 


Multiple: N=3, TDL=75, Mean=25.0, (0.067) 


m: 


1, 


(0.333), 


2.00, 


2.0, 


0.0005 




\t: 


2, 


(0.667), 


36.50, 


73.0, 


0.0010 




b: 


1, 


(0.250), 


67.00, 


67.0. 


0.0005 




/ c: 


1, 


(0.250), 


0.00, 


0.0, 


0.0O05 


\Trunk: N=4, TDL-76, Mean 190. (0.089) / 


-^m: 


1, 


(0.250), 


9.00, 


9.0, 


0.0005 




\t: 


1, 


(0.250), 


0.00, 


0.0, 


0.0005 




b: 


72, 


(0.153), 


15.24, 


1,097.3, 


0.0376 




A 


357. 


(0.760), 


2.49, 


888.9, 


0.1866 


Arm: N=470, TDL=2 i 311, Mean=4.92, (0.394) A 


^m: 


33, 


(0.070), 


7.85, 


259.1, 


0.0173 


1 


No: 


4, 


(0.009), 


12.25, 


49.0, 


0.002 1 




\, 


4, 


(0.009), 


4.50, 


18.0, 


0.0021 




b: 


23, 


(0.089), 


27.39, 


630.0, 


0.0120 




/ c: 


139, 


(0.537), 


0.75, 


104.3, 


0.0727 


Head: N=259, TDL=-1058, Mean»4.08, (0.217)/ 


/ d: 


61, 


(0.236), 


1.44, 


87.8, 


0.0319 




C\m: 


21, 


(0.081), 


3.81, 


. 80.0, 


0.01 10 




\o: 


15, 


(0.058), 


10.40, 


156.0, 


0.0078 




b: 


56, 


(0.202), 


41.63, 


2,331.3, 


0.0293 




A 


175, 


(0.632), 


5.70, 


997 5. 


0.0915 


Leg: N=277, T0L=3,898, Mean=14.07, (0.232)/ 


^m: 


27, 


(0.097), 


15.00, 


405.0, 


0.0141 


\ 


Xo: 


8, 


(0.029), 


3.88, 


31.0, 


0.0042 




\.= 


11, 


(0.040), 


12.09, 


133.0, 


0.0058 




b: 


4, 


(0.057), 


157.25, 


629.0, 


0.002 1 




/ c: 


24, 


(0.343), 


22.46, 


539.0, 


0.0125 


^Multiple: N=70, TDL=2,618, Mean=37.40, (0.059) / 


^^ m: 


39, 


(0.557), 


36.90, 


1,439.1, 


0.0204 






\o: 


3, 


(0.043), 


3.67, 


11.0, 


0.0016 




b: 


2, 


(0.100), 


12.00, 


24.0, 


0.0010 




/ c: 


7, 


(0.350), 


1.57, 


11.0, 


0.0037 


\Neck: N=20, TDL=101, Mean=5.05, (0.017) Z 


m: 


2, 


(0.100), 


29.50, 


59.0, 


0.0010 




\\° : 


3, 


(0.150),. 


0.33, 


1.0, 


0.0016 




\t: 


6, 


(0.300), 


1.00, 


6.0, 


0.0031 




b: 


22, 


(0.227), 


28.18, 


620 0, 


0.01 15 




/ c: 


58, 


(0.598), 


7.21, 


418.2, 


0.0303 


\Trunk: N=97. TDL=1,343, Mean = 1 3.85, (0.08 1) / 


' m: 


2, 


(0.021), 


4.50, 


9.0, 


0.0010 




\\° : 


7, 


(0.072), 


17.29, 


121.0, 


0.0037 




\t: 


8, 


(0.082), 


21.88, 


175.0, 


0.0042 



Figure 3.— Tree-branching diagram showing the sequence of injury components associated with jackleg drill accidents in under- 
ground metal-nonmetal mining for the 1978-83 period— Continued. 



38 



Pick 

up 

drill 




Corry 

drill 


1 Set 

—J drill 

1 down 




Pick 
up 
steel 


— 


Insert 

in 
chuck 























i 






















Position 
drill and 
drill steel 




Collar 

the 

hole 


- m 


Drill 
the 
hole 


--«■ 


Pull 
drill 
back 




Swing drill 

to new 
location 






1 


f 
















r 




Lean 

drill 

against 

rock face 























Figure 4. — Typical procedure for using the jackleg drill. 

(usually the left), while the other hand supported and 
balanced the drill. Essentially, the miner would throw the 
drill steel up in the air and would catch it further down its 
length so it could be inserted in the drill. Thus, these five 
elements of the jackleg drill operation were included in the 
development of hypotheses related to accident possibilities. 
The following is a partial listing of the questions developed 
for the five elements. 

1. Carrying the drill.— Because the jackleg drill typical- 
ly weighs over 110 lb, the manner in which it is handled 
can have a definite impact on the operator. The drill is 
usually carried either by resting the leg on the shoulder, 
or cradling the drill with one arm and gripping the "D" han- 
dle on the feed leg with the other hand. The first method 
results in large shear forces on the spine, and high static 
force requirements on the muscles of the lower back. The 
second method allows the drill to be carried closer to the 
body, thereby minimizing the forward torque. Modification 
of the carrying method through placement of a handle on 
the drill body or a carrying strap may reduce the loading 
placed on the operator. 

(a) Will the addition of a handle, which would be 
located on the top of the drill casing and in front of the 
feedleg connection, reduce the muscular forces required to 
carry the drill? 

(b) Would the addition of a carrying strap that is de- 
signed to go around the back of the neck reduce the 
biomechanical and/or physiological requirements, when car- 
rying the drill? 

(c) Can a recommended method, supported by mus- 
cle electrical activity, be developed so muscular force re- 
quirements are minimized, thus reducing the risks of in- 
jury when the drill is lowered from the shoulder? 

2. Inserting the drill steel— The typical method involves 
supporting the drill with one hand, while throwing the drill 
steel up and catching it near the lower end with the other 
hand. This can cause a large unexpected loading to the 
forearm if the steel moves to a less vertical orientation. Sup- 
porting the drill steel at the lower end with only one hand 
places significant torque about the wrist. Hence, this 
method of handling drill steels should be of concern with 
respect to cumulative trauma disorders. Although this 
technique may not be a direct cause of arm exertion injuries, 
the repeated loadings on the hand, wrist, forearm, and elbow 
maybe a contributing cause for other arm injuries. 

(a) Which muscles and joints are primarily affected 
by the forces imposed by this particular method of han- 
dling the drill steels? 

(b) Are miners prepared for unexpected loadings on 
the wrist if the drill steel moves into a nonvertical position 
when it is thrown upward? 

3. Positioning the drill.— Positioning the drill involves 
the miner balancing it with one hand, while manipulating 
it toward the rock face to be drilled with the other hand. 



This task element involves the miner counteracting ex- 
pected and unexpected forward and possibly sideways 
movements caused by the instability of the drill. A sam- 
pling of the accident narratives indicated that trunk exer- 
tion injuries occurred when miners attempted to prevent 
drills from falling. Research 6 has indicated that the effect 
of unexpected loading essentially makes the muscles re- 
spond the same as they would to twice the weight of an ex- 
pected loading. Thus, an unexpected 10-lb load elicits a mus- 
cle response that is the same as that generated by a 20-lb 
expected loading. Modifications to the tool design or the 
method of use may be developed that will reduce the 
possibility of large unexpected loads and the associated ex- 
ertion injuries. 

(a) Can the muscular forces required during drill posi- 
tioning be reduced by the addition of a handle on top of the 
drill casing in front of the feed leg connection? 

(b) Will the time required to position the drill bit be 
reduced with the addition of the handle on the drill? 

4. Collaring the hole.— Collaring the hole, which is get- 
ting the hole started to a depth of just 1/2 in or so, requires 
the drill operator to assume a static working posture. The 
maximal force that a miner can exert, therefore, will 
decrease rapidly with the time required for collaring. While 
the hole is being collared, the operator has to hold the drill 
steel with the left hand and stabilize the tool with the other. 
Once the drill steel and bit are positioned against the rock 
face, the left hand is removed from the drill steel and is 
used to turn the drill to low speed to begin moderate drill- 
ing. Measurements of muscle activity will be useful to 
establish the relative force requirements, and the role of 
fatigue in different collaring techniques. 

(a) Can various stances be used effectively when col- 
laring a drill hole? 

(b) Are there optimal body positions for different hole 
heights that will minimize the strength requirements to ef- 
fectively collar the hole? 

5. Removing the drill steel.— A sampling of the nar- 
ratives of the jackleg accidents indicate that exertion in- 
juries are related to drill steel removal. The videotapes 
revealed that the drill operators jerked on the drill one to 
three times to pull the steel and bit from the completed hole. 
The lower holes represented more of a problem because the 
bit can become jammed in the hole because of the rock cut- 
tings. Additionally, more strength is required to pull the 
drill steel free of a lower hole because the weight of the drill 
has to be lifted at the same time the drill steel is being jerk- 
ed free. Finally, when pulling the drill steel and bit free 
of a hole that is angled downward, the posture of the drill 
operator is flexed forward severely. The jerking actions can 
cause intense loading to the lumbar spine. 

(a) Will the addition of the handle to the drill casing 
make it easier to pull the drill steel free from a lower hole? 

(b) Can suggestions be made to the usual method of 
pulling the drill steel out of lower holes that will decrease 
the loading to the operator's lower back? 

In summary, consideration of the developed hypotheses 
indicated that excessive muscle forces are routinely ex- 
perienced. Asymmetrical loading occurs to the drill 
operator's back because of the weight and instability of the 
jackleg drill, and also because of the bulkiness of the 2-in 
air line that is attached to the right side of the drill. Also, 
unexpected loadings occur quite easily and frequently. 



* Marras, W. S., S. L. Rangarajuly, and S. A. Lavender. Trunk Loading 
and Expectation, Ergonomics, v. 30, No. 3, 1987, pp. 549-560. 



39 



When the drill slips and starts to fall, the operator usually 
tries to prevent it from falling. The arms, shoulders, and 
upper and lower back can be easily stressed quite 
dramatically by this reflex action. Additionally, the 
dynamics of the task or actions of the opertor trying to pre- 
vent an accident can cause severe loading from overcompen- 
sation or the excessive co-activation of the agonist- 
antagonist muscle pairs. 

After extensive analysis and consideration, the re- 
searchers feel that many of the struck-by accidents are 
related to insufficient trunk strength. Because of unex- 
pected or excessive loadings, and a corresponding inade- 
quate back strength, the drill or drill steel can impact the 
arm, leg, head, or neck. Thus, the root of the problem may 
be insufficient muscle control or excessive fatigue. 



LABORATORY STUDY 

To investigate the hypotheses that were developed, a 
laboratory experiment has been developed. The objective 
of the experiment is to interpret the trunk muscle loadings 
that occur during the four task elements that have been 
identified as requiring heavy muscular effort for their com- 
pletion. A handle has been designed and fabricated for the 
drill casing; it is positioned on the drill body in front of the 
feed leg connection. Electromyographic (EMG) data have 
been collected from six trunk muscles— the right and left 
latissimus dorsi (RLD and LLD), right and left erector 
spinae (RES and LES), and right and left rectus abdominus 
(RRA and LRA)— from eight test subjects. 

Subjects 

At the time this paper was prepared, six of the eight 
test subjects had been tested. The eight subjects are not 
miners, but all are familiar with typical underground min- 
ing conditions. As such, however, the subjects are novices, 



and all require some training with the jackleg drill so it 
can be operated safely. The test subjects will range in age 
from 23 to 39, and all are greater than the 50th percentile 
in height and weight. All subjects are in good physical con- 
dition and none has a history of significant back problems. 
All subjects are volunteers; each is required to fill out an 
informed consent form and complete a medical history form. 



Test Apparatus 

A simulated underground mine workplace was con- 
structed at Ohio State University for this investigation. The 
underground workplace, shown in figure 5, consisted of an 
adjustable-height roof; a simulated rock face for use in posi- 
tioning, collaring, and removing the drill steel; and a floor 
that consisted of 4 in of loose rock and gravel. The room 
in which the simulated workplace was constructed was 28 
ft long, 10 ft wide and 11-1/2 ft high. The simulated work 
area was approximately 12-1/2 ft long and 7 ft wide. 

The simulated rock face consisted of a wall of standard 
2- by 4-in studs, 10 ft in length, nailed together face to face; 
thus the drill rested against the edges of the 2 by 4's. This 
wall consisted of 44 studs nailed together. The overall 
dimensions of the simulated rock face were 5-ft width, 10-ft 
height, and 3-3/8-in thickness (actual dimensions of a 2- by 
4-in stud are 1-3/8 by 3-3/8-in). 

A series of eight holes were drilled into the simulated 
face. Four of them were drilled entirely through the wall 
and the other four were drilled only halfway into it. The 
holes were located at heights of 22, 43, 68, and 92 in above 
the rock and gravel floor. 

Large pipe caps were placed into the holes that were 
drilled halfway through the wall. This arrangement was 
used for the collaring element of the simulation. A drill steel 
with no bit on it was positioned inside a pipe cap, and the 
drill was set at a low speed, as if a drill hole was to be started 
(collared). The holes that were drilled entirely through the 




Figure 5.— Layout of the simulated underground workplace for conducting tests with the jackleg drill. 



40 



wall were used to simulate the positioning and removal 
elements. 

Bracing for the simulated face took up 6 ft of the room. 
The other 9 1/2 ft of the room contained the data collection 
instrumentation. A protective metal fence separated the 
simulated workplace from the data collection portion of the 
room. 

Experimental Design 

The independent variables for this experiment were the 
hole heights and the presence or absence of the handle that 
was fabricated for the drill casing. Three of the four hole 
heights were used during the testing. The 22-in height was 
used for the lower hole simulation. The 43-in height was 
used for the horizontal work, and the 92-in height was us- 
ed for the overhead hole positioning, collaring, and removal. 
The dependent variable was the EMG activity of the six 
trunk muscles for each of the four elements (carrying the 
drill, positioning the drill steel, collaring the hole, and 
removing the drill steel). 

As mentioned, all subjects were familiar with the 
underground mining environment, but were novices regard- 
ing the operation of a jackleg drill. All subjects were re- 
quired to go through one to three training sessions to 
become familiar with the safe operation of this drill. 

Data Collection Equipment 

The surface EMG electrodes were attached to the sub- 
ject's torso at the six muscle sites (right and left latissimus 
dorsi, erector spinae, and rectus abdominus). The location 
of the electrodes was verified through functional muscle 
testing. The electrode locations and attachments were 
prepared according to standard procedures. 7 Skin resistance 
was measured to verify the conductivity of the electrode- 
skin attachment. The electrodes were connected to small 
lightweight preamplifers that were attached with Velcro 8 



7 Basmajian, J. V. Muscles Alive: Their Functions Revealed by Electro- 
myography. William and Wilkins, 1979, 561 pp. 

8 Reference to specific products does not imply endorsement by the Bureau 
of Mines. 



hook-and-loop fasteners to a belt around the subject's waist. 
This assured that the electrodes were in close proximity to 
the preamplifiers to reduce any interference in the EMG 
signal. 

Six pairs of electrodes and one ground electrode were 
connected to the EMG amplifiers. The EMG signal was con- 
ditioned with high- and low-pass filters and integrated by 
a hardware root-mean-square (RMS) procedure. The six 
EMG signals were monitored by an ISAAC 2000 data ac- 
quisition system. This system uses a microprocessor to con- 
vert analog signals to digital form. A Schmitt trigger was 
incorporated into the data collection system to document 
the temporal aspects of the experiment. 

After each experimental trial, the data were transferred 
to a microcomputer for viewing on a graphics display. This 
ensured that all signals were active throughout each por- 
tion of the experiment. The data were then stored for fur- 
ther analysis. Figure 6 presents a schematic of the data ac- 
quisition system. 

Experimental Task 

The subjects were asked to warm up by bending and 
stretching before beginning the experiment. Before the ac- 
tual testing, a pretest was conducted. The pretest consisted 
of recording the maximum voluntary contraction, as well 
as the resting levels, of each muscle group. 

During the testing, each subject performed the follow- 
ing tasks: (1) pick up the jackleg drill, carry it approximately 
10 ft, set it down and lean it against the simulated face; 
(2) insert the drill steel (with no bit) into the three holes 
(22-, 43-, and 92-in heights) with pipe caps inserted into 
them so the drill could be started as if the holes were being 
collared; (3) balance the drill and insert the drill steel into 
the holes (at the same three heights) that were drilled 
through the wall, and extend the feed leg so the drill body 
touches the wall; (4) release the feed leg so the drill could 
be pulled away from the wall, and remove the drill steel 
from the same three holes. These task elements were ran- 
domized to reduce any bias from order of conducting the 
tasks. Two repetitions of each task element were recorded, 
and a 2-min rest period was provided between exertions. 



Jackleg drill 7 i 



Electromyographic 
channels 



Electromyographic 
preamplifiers 




CRT 



Switch 
box 



Analog- 
digital 
data 
acquisition 



Personal 
computer 



Integrators 
Amplifiers and filters 



Mainframe 
computer 



Plotter Printer 



Figure 6.— Data acquisition system for the jackleg drill testing. 



41 



PRELIMINARY RESULTS 



As mentioned in the previous section, six of the sched- 
uled eight subjects had been tested at the time this paper 
was prepared. Additionally, only data from the first sub- 
ject had been analyzed. As such, the analysis obtained thus 
far is quite preliminary and no trends can be identified just 
yet. Figures 7 and 8 are presented to show typical EMG data 
obtained during the testing. Figure 7 presents the electrical 
activity from the three muscle groups when collaring the 
low hole (22-in height). Figure 8 presents EMG data for the 
trunk muscles of the same subject but collaring the high 
hole (92-in height). 



Figure 7 shows a distinctive double peak in the muscle 
activity. The initial burst of activity relates to orienting the 
drill steel into the lower pipe cap. The low activity in the 
middle of the sample is when the drill is turned to a low 
speed to simulate the collaring of the hole. The second burst 
of muscular activity occurs after the drill is turned off and 
then pulled back from the face. During this exertion, the 
RLD and the RES muscles exhibited a very dramatic rise 
in electrical activity. The LLD and LES developed the next 
highest activity. Both abdominal muscles showed very lit- 
tle activity during this entire task. 



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Rectus abdominus left 
Rectus abdominus right 
Erector spinae left 
Erector spinae right 
Latissimus dorsi left 
Latissimus dorsi right 



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J 1 I I I I I 1 I L 



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Figure 7.— Integrated EMG data for six trunk muscles of one subject while handling the jackleg 
drill at low-hole height (22 in). 



42 



Figure 8 shows that the initial burst of muscle activity 
occurs more rapidly for the high hole than the low hole, but 
the peak value for the high hole is 56 ^V versus 64 f/V for 
the low hole. Again the initial electrical activity involves 
the RLD and the RES during the drill steel orienting. 
Similar to figure 7, the LLD and LES are the next most 
active, and the abdominal muscles were fairly inactive. 

The middle portion of the overall exertion was quite dif- 
ferent in this figure. Much more activity was exhibited for 
the high hole than the low hole. The beginning of the col- 
laring had the RLD and LES the most active. Rather quick- 
ly, however, the activity of the LLD exceeded that of the 
LES. In fact, for a brief 3-s interval, the electrical activity 
of both of the abdominal muscles exceeded the activity of 
both erectores. 

The second activity (pulling the drill back from the face) 
is not as clearly delineated for the high hole. This is con- 
sistent with the accident narratives and the developed 



hypotheses. The major effort for pulling the drill back from 
the face occurs much more noticeably for the lower holes. 
At 17 s lapsed time, there are slight peaks for the RLD and 
both erector spinae muscles. At the same time, the activity 
for the two abdominals drops off quite noticeably. Looking 
at the low-hole data, the RLD and RES muscles are the most 
active throughout this entire task. This seems to indicate 
definite asymmetrical loading. 

For the high hole, the RLD dominates throughout the 
task. The RES starts out with the second highest activity, 
but within a few seconds, the electrical activity of the LES 
clearly exceeds the RES and for a brief while is as active 
as the RLD. Approximately halfway through the task the 
activity of the LLD increases steadily and actually exceeds 
that of the RLD for 3 s or so. At 17 s lapsed time (when the 
drill is pulled back from the face), the LLD drops off quite 
noticeably. 



68 

51 

34 



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e> 

</> 

o 68 

I 
a. 

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or 
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KEY 

Rectus abdominus left 

Rectus abdominus right 

Erector spinae left 

Erector spinae right 

Latissimus dorsi right 

Latissimus dorsi left 



_i I I I I I L 




17 










Figure 8.— Integrated EMG data for six trunk muscles of one subject while handling the 
jackleg drill at high-hole height (92 in). 



43 



SUMMARY 

The task analyses have identified problem areas during the manipulation of the drill at the low-hole height 

associated with using the jackleg drill. The hypotheses that (22 in). 

have been developed have helped to focus the methods with Data analysis has not been completed for the conditions 

which these problems can be addressed and researched in with the handle attached to the drill casing. Responses from 

controlled laboratory conditions. four of the six test subjects, however, have been favorable. 

Although only two EMG graphs are presented, they give All six subjects feel as if the addition of the handle makes 

some indication as to the muscular activity required when it easier to pull the drill steel out of the lower hole, 
operating the jackleg drill. Asymmetric loading is indicated 



44 



COMPUTER-AIDED ANALYSIS OF HUMAN FACTORS ASPECTS 

OF MINING CREWSTATIONS 



By Richard L. linger 1 and James P. Rider 2 



ABSTRACT 

The Bureau of Mines is researching a computer-aided analysis model for mining 
machine operator compartments. Based on proven models used in both the public and 
private sectors, and original software being developed by the Bureau, the model will 
perform the following: reach assessment, visibility analysis, structural analysis of pro- 
tective canopy designs, illumination analysis (including both disability and discomfort 
glare ratings), operator fatigue analysis, and computation of an ingress-egress rating. 
The model will make extensive use of graphics to simplify data input and output. A 
three-dimensional manikin is used as the subject for many of the analyses. The model 
is intended for use by equipment manufacturers and mining companies during initial 
design work on new machines, and for evaluating proposed modifications to existing 
machines. The Bureau also plans to use the model as an accident investigation tool, 
where it can be used to reconstruct the events leading to certain equipment-related 
accidents. 



INTRODUCTION 



Use of computers is becoming an increasingly accept- 
able technique for equipment designers. Computer-aided 
design (CAD) replaces the traditional drawing board with 
a graphics monitor and input device. 

By using the computer, the designer has a flexibility 
to experiment that is not practical with conventional tech- 
niques. Drawing information is stored in a data file and 
simultaneously displayed to the designer. The design proc- 
ess is accelerated by the speed with which the computer 
converts the designer's input into digital form, with an ac- 
curacy difficult to achieve with a pencil or pen. Once 
created, drawings can be scaled and plotted in seconds. 

Modifications and changes can be made with even 
greater efficiency. Changing one element of a shape for ex- 
ample, can automatically result in suitable changes in all 
other related lines and dimensions of that shape. The size 
of an object can be scaled up or down instantly. Once drawn 
on the CAD system, any object can be recalled, rescaled, 
and added to a new design without tedious redrawing. 

Through use of a CAD system, a designer's productiv- 
ity can be increased significantly. There is no doubt that 
CAD is the way of the future and will eventually replace 
the manual drafting board in most engineering offices. As 
it relates to the human engineering of equipment, CAD can 



provide assistance by displaying three-dimensional views 
of objects and assemblies, so that the designer can better 
visualize potential problem areas. Unfortunately, while 
CAD systems make the design process more efficient, their 
use can lead to problems. 

The environment of the CAD facility promotes work out- 
put and efficiency, but not thought and consideration. The 
CAD system usually incorporates a very expensive work- 
station, and designers oftentimes must schedule time on the 
system. Two- and three-shift utilization of CAD facilities 
is not uncommon. This situation does not promote the long 
periods of contemplation that designers have traditionally 
indulged in while working at their drawing board. Also, a 
designer would rarely leave a CAD display running to go 
back and review a design reference manual. Rather, the 
designer would most likely make a note to look up the in- 
formation and perhaps correct the problem at a later ses- 
sion. So, while the CAD system is a tool of unprecedented 
power and capability, the designer is pressed by that same 
power to avoid the pauses associated with consideration (l). 3 

Another problem is that CAD systems usually provide 
no means to consider the interface between the equipment 
being designed and the operator who is using it. The tradi- 
tional method of doing this is to build mockups and perform 
"fitting trials," using a sample of the eventual operators 



'Civil engineer. 
"Operations research analyst. 
Pittsburgh Research Center, Bureau of Mines, Pittsburgh, PA. 



'Italic numbers in parentheses refer to items in the list of references 
preceding the appendix at the end of this paper. 



45 



of the equipment. This approach is necessary to ensure that 
a design meets accepted human engineering specifications. 
However, because of the time and expense involved, it often 
means that many parts of the design are finalized without 
consideration of the human operator (2). 

The design of underground mining machinery has 
generally stressed the technical and engineering aspects 
related to the machine's functions over the needs of its 
human operators. This has resulted in machines that strain 
the capabilities of their operators and contribute to the high 
accident rate among operators or riders of underground coal 
mobile equipment. As an example, in 1984 there were 1,822 
injuries to miners while operating or riding in underground 
mobile equipment. This amounts to 17 pet of all the injuries 
that occurred in underground coal mining during that year. 

In many cases the injuries can be directly related to the 
design of the machine operator compartments. As shown 
in figure 1, oftentimes operators must lean outside the safe 
confines of the vehicle compartment in order to operate the 
vehicle, thereby increasing the likelihood of their striking 



the rib or roof. Controls are often unlabeled and placed 
where they are difficult to reach and distinguish from one 
another. In panic situations, the wrong control may be 
activated, which could lead to accidents or injuries. 

In order to address these problems, the Bureau is 
developing a computer-based model to aid in the human 
engineering aspects of mining equipment design. The 
model, known as crewstation analysis programs (CAP), is 
now in the middle stages of a 10-yr development program. 
It is intended for use by original equipment manufacturers 
and mining companies for the initial design work on new 
machines, and to evaluate proposed modifications to 
existing machines based on good ergonomic design 
principles. 

The purpose of this paper is to outline the overall struc- 
ture of CAP and provide background on two of its analysis 
sections, specifically, the visibility analysis and the 
illumination analysis. Interested readers are invited to con- 
tact the Bureau of Mines, Pittsburgh Research Center, for 
more information on the CAP model. 




Figure 1 .—Cramped operator stations and poor visibility often force miners to lean outside the safe confines of the cab. 



46 



OVERVIEW OF CAP 



When work on this project began, it was decided to take 
advantage of as much publicly available software as possi- 
ble. This was to both keep the final cost of the model low, 
and avoid spending time in unnecessarily repeating the 
work of others. Original software developed by the Bureau 
under its health and safety research program is free to the 
public upon its completion, so the final cost of implement- 
ing CAP at a particular site will consist mainly of the 
expenses of the hardware needed. 

CAP is designed to work with Tektronix computer dis- 
play terminals (model 4111), hard copy units, and graphics 
tablets 4 as shown in figure 2. Some sections of the model 
require no graphics and can be run on virtually any ter- 
minal. CAP is written in Fortran and is currently imple- 
mented on a VAX 780 and Microvax II computer network 
at the Bureau's Pittsburgh Research Center. 

For the sake of simplicity, CAP can be thought of as 
being composed of the following major analysis sections, as 
shown in figure 3. 

1. Anthropometric (reach) analysis. 

2. Visibility analysis. 

3. Illumination analysis. 

4. Canopy structural analysis. 

The first section determines whether the controls are 
reachable for a given sample population and provides infor- 
mation for the best positioning of controls. The fourth analy- 
sis section determines if the protective canopy meets the 
requirements of the Federal Coal Mine Health and Safety 
Act of 1969. The applications of the visibility and illumi- 
nation analyses sections are discussed in detail later in 
this paper. 

'Reference to specific products does not imply endorsement by the Bureau 
of Mines. 



In addition, research related to the model is continu- 
ing and the following sections will be added: 

5. Fatigue analysis.— Assigns a numerical value for 
rating the overall positioning of an operator in a particular 
crewstation. 

6. Dynamic positioning and timing of movements 
analysis.— Measures the ability of an operator to exit the 
cab and the time required to reach designated controls. 

Each of these six sections address an important aspect 
of the machine's design with respect to human engineering. 

Before any analysis can begin, data defining the min- 
ing machine, mine layout, or population sample must be 
entered into the computer. CAP will allow two techniques 
for constructing three-dimensional models of mining 
machines and operator compartments. The first method, not 
yet implemented, is to build the model using three- 
dimensional body types such as blocks, wedges, cones, ellip- 
tical cylinders, and spheres as shown in figure 4 and table 
1. The user defines the dimensions of each body type and 
its orientation in a three-dimensional coordinate system. 
In this way, combinations of shapes can be used to construct 
practically any geometry needed to perform an analysis. As 
an example, figure 5 is a photograph of an underground 
forklift developed by the Bureau and figure 6 is the three- 
dimensional model of the forklift constructed using the 
preceding technique. 

The major drawback to this construction method is that 
it is time consuming for the user to compute the sizes and 
locations of the shapes needed, and then to input them into 
the computer. For this reason, a second machine geometry 
method is being provided. 




Figure 2.— Some of the computer graphics equipment used for the CAP model. 



Data inout: 
mine layout 



Data input: 
population sample 



Data input: 
machine model 



Anthropometric 
(reach) 
analysis 



Crewstation analysis programs 

(CAP) 



User interface 
(data input, output, help, menu choices, etc.) 



Visibility 
analysis 



Illumination 
analysis 





Future 


work 










! 


Fatique 
analysis 




Timing of movements, 

dynamic positioning 

analysis 





Figure 3.— Overview of CAP. 



47 



Hardware: 
VAX780 or Microvax 
Colorgraphics workstation 
Color copier 
Plotter 
Digitizing tablet 



Canopy 
structural 
analysis 



WEDGE 



CYLINDER 




POLYHEDRON 





TRUNCATED CONE 



V| V. 



SPHERE 



ELLIPSOID 




BOX 





L 




^J 


ijy 



Figure 4.— Body types used in machine model construction. 



Table 1.— Body type, description, and input parameters 1 

Body type Description Parameters 

Box 6-sided parallelepiped V x , V y , V z . 

L1 X , L1„, L1 2 . 
L2 X , L2 y , L2 Z . 
L3 X , L3y, L3 Z . 

Wedge A "box" cut along a diagonal. V x , V y , V z . 

L1 X , L1 y , L1 z . 
L2 X , L2 y , L2 Z . 
L3 X , L3y, L3 Z . 

Polyhedron 6-sided convex figure Vn x , Vn y , Vn z , 

where n = 1 to 
8; also faces 1 
through 6, 
where the face 
value is given 
by the cardinal 
numbers of its 
4 vertices. 

Sphere A rotated circle defined by its V x , V y , V z . 

center and radius. R. 

Ellipsoid A rotate ellipse defined by its V1 x , V1 y , V1 z . 

two foci and the length of its V2 X , V2 y , V2 Z . 
major axis. L. 

Cylinder A projected circle V x , V y , V z . 

H x , n y , H z . 
R. 

Truncated Similar to a cylinder, but with V x , V„, V z . 
cone. a second radius specified. H x , H y , H z . 
R1, R2. 

''See figure 4 for identification of parameters. 



48 




Figure 5.— Prototype battery-powered underground forklift. 




Figure 6.— Three-dimensional model of a forklift created using 
method 1. 



This second method makes use of a graphics tablet to 
digitize significant points from orthographic projection 
drawings of the desired machine as shown in figure 7. The 
digitized points are stored for later use in a routine that 
will convert the two-dimensional drawings into a three- 
dimensional object. The greatest asset of this technique is 
that the identification of three-dimensional points from the 
two-dimensional drawings is done by the computer. Thus, 
the user needs very little knowledge of three-dimensional 
geometry. The difficulty in this approach is that the 
orthographic projection drawings, though simplified ver- 
sions of the real machine, must be drawn very accurately 
and contain any hidden lines representing desired details. 
Figure 8 illustrates a shuttle car reconstructed using this 
technique. 

The use of either method results in three-dimensional 
models that contain errors. Therefore, the user will have 
the option to go back and adjust the model using an inter- 
active procedure. There is also a library of common shapes 
and mechanisms that the user may insert into the model 



wherever needed. For example, a common seat design need 
not be digitized repeatedly, but only has to be called up from 
a file and inserted in the operator station. 

On certain analyses, such as the illumination analysis 
or visibility analysis, or when the user is attempting to 
reconstruct mobile equipment related accidents, it is 
necessary to create a mine scene. This is done with a tech- 
nique similar to that which is used in method 1 of entering 
mining machine geometries. The user defines the dimen- 
sions and orientations of certain standard underground min- 
ing structures, such as cribbing sets, pillars, railroads, and 
stoppings. Crosshairs are used to make it easier for the user 
to pinpoint the exact locations where objects should go. The 
mine layout may be modified and used repeatedly for dif- 
ferent analyses. 

Most of the analysis sections of CAP require a sample 
population for testing. CAP allows the user to input either 
the actual external anthropometric measurements for one 
or more individuals directly, or to generate a sample popula- 
tion from the means, standard deviations, and correlations 
of a set of anthropometric measurements using statistical 
methods. This second technique is an adaptation of that 
used in the crewstation assessment of reach (CAR) program 
developed by the Boeing Aerospace Corporation for the 
Naval Air Development Center (3). The external 
measurements for the sample population are transformed 
into internal link lengths and link circumferences, and are 
used to create either a link-person or a three-dimensional 
manikin as shown in figure 9. The external measurements 
required are presented in figure 10. 

Once the necessary data has been entered, the user is 
free to choose any analysis section desired. At any point 
the user may go back and modify the mine or machine 
model or sample population based on the analysis results. 
The remainder of this paper describes the visibility and 
illumination analysis sections in brief detail as they are cur- 
rently implemented. 



49 




FRONT 
Figure 7.— Typical orthographic projection drawings used for digitization. 




Figure 8.— Three-dimensional reconstruction of a shuttle car using method 2. 



50 




Stature 




Bideltoid 
diam 



rearm -hand 
ength 



Sitting, 

height 




Figure 9.— Three-dimensional manikin used in CAP analysis, 
equipped with hardhat and miner's boots. 



Figure 10.— External anthropometric measurements used to 
construct the three-dimensional manikin. 



51 



VISIBILITY ANALYSIS 



In the cramped and dark confines of an underground 
mine, a machine operator has extensive visibility 
requirements. It is important to distinguish the visibility 
requirements for a machine, i.e., what needs to be seen, from 
the field of visibility, i.e., what can be seen. The Bureau has 
sponsored research to determine the visibility requirements 
of many pieces of underground mining equipment. These 
visibility requirements are specified by the use of visual 
attention locations (VAL's) (4), and are positioned with 
reference to machine parts. In this way, the requirements 
will apply to all the different machine models in an equip- 
ment class. For example, operators may be required to see 
an object at ground level a minimum distance in front of 
the machine in order to stop before reaching it. This point, 
or VAL, can be located in space as follows: 

Fore-Aft: Front edge of machine and necessary stopping 
distance. 

Lateral: Machine centerline. 

Vertical: Floor. 

This requirement would not change if the length, width, 
or height of the machine changed, or if the operator's eye 
position changed. Thus, the requirements are applicable to 
all equipment in a given class, i.e., all continuous miners, 
all shuttle cars, etc. Table 2 contains the coordinates (fore- 
aft, lateral, and vertical) for each of 54 recommended visual 
attention locations associated with operation of shuttle cars. 
The table is grouped into 20 fore-aft, lateral positions, at 
which from one to four vertical heights are indicated. Figure 
11 presents a schematic illustrating these 20 positions. At 
each position in figure 11 are numbers that correspond to 



the recommended VAL's in table 2. In the case of shuttle 
cars, these 54 requirements apply to both directions of 
travel. 

CAP allows the user to create an operator's eye view 
of the surrounding environment for an assessment of the 
visibility of VAL's. The users may place their "eye" posi- 
tion and orientate their lines of sight in any way that con- 
forms to the anchor point of the three-dimensional manikin 
and the acceptable limits of motion of the human body. The 
view from the operator's station is drawn, taking into 
account the field of vision at the eye, and the user then notes 
which VAL's can be seen and what modifications may be 
needed in the machine design. The analysis is performed 
repetitively, with the user making judgments as to where 
the three-dimensional manikin should "look." Figure 12 
illustrates several views from the cab of a shuttle car, and 
figure 13 presents an overall view of the VAL's around the 
shuttle car. 

An optional visibility analysis procedure now being 
worked on is basically a computer simulation of the 
experiments described by Canyon Research (4). CAP is used 
to generate either (1) a range of eye locations for a sample 
of individuals placed in a common configuration or (2) a 
range of eye locations for a single representative individual 
through a series of configurations. For each VAL, the 
graphics processor is used to determine the portion of the 
range "seen" from each VAL. If a sample of individuals is 
used, CAP reports the percentage of operators capable of 
seeing the VAL; if a single individual is analyzed, CAP 
reports whether the VAL can be seen or not. 



52 



Table 2.— Recommended visual attention locations (VAL's) for shuttle cars 

Recom- 
Fore-aft, lateral position mended 

VAU 

1— rear edge, machine centerline 1 

2 

2 — operator's head, machine centerline 3 

4 

3 — operator's head, widest machine point 2 plus 3ft 5 

4— front edge plus 2 ft, widest machine point 2 plus half NSD 6 

7 

5 — front edge plus 2 ft, widest machine point 2 plus 3ft 8 

9 

10 
11 

6 — front edge, machine centerline 12 

13 
14 
15 

7 — front edge plus 2 ft, widest machine point 3 plus 2ft 16 

17 

18 

8 — front edge plus 2 ft, widest machine point 3 plus half NSD 19 

20 

21 
22 

9 — front edge plus half NSD, widest machine point 3 plus half NSD 23 

24 
25 

10— front edge plus half NSD, widest machine point 3 plus 2 ft 26 

27 

11— front edge plus half NSD, machine centerline 28 

29 

1 2— front edge plus half NSD, operator centerline 30 

31 

13 — front edge plus half NSD, widest machine point 2 plus 3 ft 32 

33 

34 

14 — front edge plus half NSD, widest machine point 2 plus half NSD 35 

36 

15 — front end plus NSD, widest machine point 2 plus half NSD 37 

38 
39 

16 — front edge plus NSD, widest machine point 2 plus 2 ft | 40 

41 
42 

1 7 — front edge plus NSD, operator centerline 43 

44 

18 — front edge plus NSD, machine centerline 45 

46 

47 
48 

1 9— front edge plus NSD, widest machine point 3 49 

50 
51 

20— front edge plus NSD, widest machine point 3 plus half NSD 52 

53 
54 

NSD Necessary stopping distance. ^ee figure 11. 2 Same side as operator. 3 Opposite side of operator. 



Vertical height 



Operator eye height. 

Highest machine point. 

Operator eye height. 

Highest machine point. 

Operator eye height. 

Floor. 

Highest machine point. 

Floor. 

Median machine 

height. 
Operator eye height. 
Highest machine point. 
Median machine point. 
Operator eye height. 
Highest machine point. 
Seam height. 
Floor. 
Median machine 

height. 
Highest machine point. 
Floor. 
Median machine 

height. 
Operator eye height. 
Highest machine point. 
Floor. 

Operator eye height. 
Highest machine point. 
Floor. 

Highest machine point. 
Median machine 

height. 
Seam height. 
Floor. 

Seam height. 
Floor. 
Median machine 

height. 
Highest machine point. 
Floor. 

Highest machine point. 
Floor. 

Operator eye height. 
Highest machine point. 
Floor. 

Operator eye height. 
Highest machine point. 
Median machine 

height. 
Highest machine point. 
Floor. 
Median machine 

height. 
Operator eye height. 
Highest machine point. 
Floor. 

Operator eye height. 
Highest machine point. 
Floor. 

Operator eye height. 
Highest machine point. 



53 



Operator centerline 
(OCL) 



5!J 



I Machine centerline 

W (MCL) 



Front edge and 
necessary stopping 
distance (nsd) -^ l 



37,38,39 



35,36 32,33,34 



r- j , » 6 . 7 8,9,10,1 

Front edge (FE)^ V 



1' 



/ 



Widest machine points 

(WMP(SS)) 



45,46 
U.44 47,48 



$9,50,51 52,53,54 

• 



,312^,29 



t 



12,13,14,15 



26,27 23,24,25 



I6J7.I8 19,20,21,22 



5 



Operator 
Operator ' s head (OH)-^ 

Rear edge (RE)-^ 



l: 



1 



M 



■z- 



Shuttle car 



10 



Scale, ft 



Figure 11.— VAL's for a shuttle car. 



54 





Figure 12.— Operator's eye view of VAL's from a shuttle car cab. Top, view from cab looking at VAL 28 (fig. 11— front edge plus 
half necessary stopping distance, machine centerline, median machine height); bottom, view from cab looking at the front lower 
left corner of machine. 



55 



* 



** 






* 



*« 




4^ 



^ 



* 



* 



* 



* 



* 



* 



Figure 13.— Overall view of VAL's around a shuttle car. 



ILLUMINATION ANALYSIS 



The purpose of this section of the CAP model is to pro- 
vide mining equipment manufacturers, mine operators, and 
the Mine Safety and Health Administration (MSHA) with 
a computerized method of evaluating mine illumination 
systems. This would allow these parties to quickly analyze 
proposed lighting configurations without resorting to the 
time-consuming method of building physical mockups and 
taking light reading manually. 

Title 30 of the Code of Federal Regulations requires that 
designated surfaces within a miner's normal field of vision 
be illuminated to 0.06 fL while self-propelled mining equip- 
ment is being operated in the working place. Different types 
of machines have different required areas of illumination. 
For example, for continuous miners, the following areas 
must be illuminated to 0.06 fL as shown in figure 14: 

1. The face. 

2. The ribs, roof, floor, and exposed surfaces of mining 
equipment, from the face to the outby end of the machine's 
bumper when shuttle car haulage is used or to the first 
transfer point when continuous conveyor haulage is used. 

In addition, the regulations require that light fixtures 
be designed and installed to minimize glare. Glare is a 
visual sensation that can result in annoyance, discomfort, 
loss of visual performance, or a reduction of visibility (5). 
Glare is a very significant factor in the design of under- 
ground coal mine illumination systems and it may signi- 
ficantly distract from the benefits of these systems. It is 
prevalent in the underground mine environment because 
luminaires must often be located close to the mine worker's 



line of sight, and they are viewed against a very dark 
background, which results in a high contrast between the 
light source and its surroundings as shown in figure 15. 

CAP will be able to analyze two types of glare, disabil- 
ity glare and discomfort glare. Disability glare is defined 
as glare resulting in reduced visual performance and visi- 
bility. It is caused by stray light, which enters the eye and 
scatters within, causing a "veiling luminance" over the 
retina, which in turn, has the effect of reducing the per- 
ceived contrast of objects being viewed. Discomfort glare 
is a sensation of annoyance or, in extreme cases, pain caused 
by high or nonuniform distribution of brightness in the field 
of view. 

Bureau research has developed methods of quantifying 
both types of glare for an underground environment. These 
methods were originally intended to be used for manual 
calculation, but have been adapted for use by the computer. 
Using the three-dimensional machine model generated by 
CAP, the user can use either graphical or numerical input 
to position and orientate specific luminaires on the machine. 
The user then specifies the location and field of vision of 
any observers around the machine. Finally, the areas re- 
quired to be illuminated, as specified by MSHA, are input. 

The analysis routines are then entered to complete the 
procedure. The routines perform the following functions: 

1. Processes the machine model. 

2. Checks the specifications on the types and locations 
of illumination sources entered by the user. 



56 



3. Checks the locations of the observers specified by the 
user. 

4. Traces simulated light rays from source locations to 
an array of measurement points (the ribs, floor, and roof 
of the mine as specified by the user). 

5. Records the incident illumination levels at each 
measurement point in an organized, easily interpreted 
format. 

6. Calculates the disability and discomfort glare for each 
observer for the given field of vision. 

The results of the illumunation analysis are given for 
each mine surface defined by the user. Each surface is 
divided into a rectangular grid of detector points, 2 ft apart. 
CAP computes the illumination, in footcandles, incident at 
each of these grid points. It also determines the average 
illumination in each 2- by 2-ft square by averaging the four 
points at the corners of each square. This corresponds to 
the actual measurement method used by MSHA. Any aver- 
age value that is below the minimum permissible level is 
marked on the grid and displayed to the user. 

The appendix presents the techniques for solving for the 
illumination at a given point in relation to a mining 
machine. 




Figure 14.— Area required to be illuminated for continuous min- 
ing machines. 




Figure 15.— Glare can be a severe problem in underground environments. 



57 



CONCLUSIONS 



The CAP program can be used by mining machine 
designers and mining companies to— 

Refine control locations to achieve maximum accommoda- 
tion for an operator sample. 

Maximize the visibility of machine operators and assess 
the ability to see the visual attention locations of mining 
machinery. 

Analyze the effects of discomfort and disability glare and 
compute the illuminance values for machine-mounted 
illumination systems on underground coal mining 
machinery. 

Conduct structural analyses of the protective canopies 
used to protect equipment operators from roof falls. 



Widespread use of this program by the mining industry 
should have a positive impact on the design of new mining 
equipment and the retrofitting of older equipment. Better 
human engineering in mining equipment is essential if pro- 
ductivity is to improve along with a reduction in the number 
of injuries. Ongoing work on CAP includes the development 
of routines to perform fatigue ratings and timing-of- 
movements analyses for operator stations based on the 
machine geometries defined by the user. 

CAP will be available for restricted distribution to 
interested mining machine manufacturers and mining com- 
panies in the fall of 1987, and reports on work done to 
validate the model's results will be published. 



REFERENCES 



1. McDaniel, J.W. Computer Aided Design Models to Support 
Ergonomics. Wright Patterson AFB, Dayton, OH. 

2. Bonney, M.C., C.A. Blunsdon, K. Case, and J.M. Porter. Man- 
Machine Interaction in Work Systems. Univ. Wottingham, United 
Kingdom, Aug. 1978, 4 pp. 

3. Harris, R.M., J. Pennett, and L. Dow. CAR II— A Revised 
Model for Crewstation Assessment of Reach (contract 
N62269-79-C-0235, Boeing Aerospace). Naval Air Development 
Center, June 1980. 



4. Sanders, M.S. Visual Attention Locations for Operating Con- 
tinuous Miners, Shuttle Cars, and Scoops: A Summary (contract 
J0387213, Canyon Res.). BuMines OFR 29(2>82, 1981, 67 pp.; NTIS 
PB 82-187949. 

5. Lewis, W.E. (comp.). Underground Coal Mine Lighting Hand- 
book, ttn Two Parts.) 1. Background. BuMines IC 9073, 1986, 42 pp. 



58 



APPENDIX 



In calculating illuminance values, the computer pro- 
gram simulates the method of measurement of illuminance 
used by MSHA when approving illumination systems by 
the Statement of Test and Evaluation (STE) approach. In 
this method, the illuminance at any point on the floor, roof, 
or ribs is defined as the peak illuminance impinging on that 
point. Peak illuminance is defined as the maximum foot- 
candle reading obtained from a photometer that is orien- 
tated in the direction of maximum illuminance as shown 
in figure A-l. 

For clarity, it should be noted that to convert this com- 
puted value of illuminance (footcandles) to luminance 
(footlamberts), the cosine law must be applied as follows: 

-^mine surface = ^peak x (COS v)), 

and the luminance is 

'-' ~ \^r> ^-"mine surface- 
where Z r is the mine surface reflectivity and L is the value 
of surface luminance, in footlamberts. 

For field-approved illumination systems, L is the value 
measured by MSHA. For STE-approved illumination 
systems, E pea k is the measured value. 

In the case of multiple luminaires, the peak illuminance 
is defined as the vector sum of the peak illuminances im- 
pinging on the point in question as illustrated in figure A-2. 
Computation of luminance to simulate the MSHA field- 
approved method is not addressed with this computer 
program. 

The basic equation for calculating the illumination at 
any point around the machine model is 

E = I/D 2 , 

where E = illuminance, footcandles, 

I = intensity of the light along the vector between 
the light sources and the point where the light 
is being measured, candles, 
and D = distance between the light source and the 
point, feet. 
There are two other variables that must be taken into 
account when performing illumination calculations. One is 
the effect of objects in the path of the light source (shadow- 
ing). The second is the location of the measurement point. 
The effects of shadowing will be discussed first. 

Assuming that the measurement point is known, the 
illumination at that point is given by the equation 



E = ^ 



D, 



J* 
D r 



(vector summation), 



where n is the number of illuminaires. 

In other words, the illumination at a specific point is 
the vector sum total of the illumination from all lamps con- 
tributing light to that point. The light is considered to be 
a vector originating at the lamp (defined as a point source) 
and ending at the measurement point. If the light vector 
intersects a plane of the machine model before reaching the 
measurement point, the effects of that light are canceled 
out of the illumination equation. Because the three- 
dimensional machine model is already stored in the com- 



puter's memory, the program is able to calculate the 
intersections of light vectors as they travel to various 
measurement points. When an intersection occurs, the con- 
tributions of that light to the illumination at that measure- 
ment point is set to zero. 

The determination of measurement points, i.e., those 
points where the computed incident light measured must 
be at least 2 fc, is directed by MSHA regulations. MSHA 
requires that incident light measurements must be taken 
for each 2- by 2-ft area on the surfaces surrounding the 
machine that have to be illuminated, as specified in the 
Code of Federal Regulations. However, there is nothing in 
the regulations that dictates where the 2- by 2-ft areas are 
to originate. Thus, the computer divides the areas surround- 
ing the machine (floor, roof, and ribs) into a rectangular grid 
of measurement points 2 ft apart. The program then com- 
putes the illumination, in footcandles, incident at each of 
these measurement points. It also determines the average 
illumination in each 2- by 2-ft grid square, by averaging 
the four points at the corners of the square. Grid squares 
with an average value below the minimum permissible level 
are shaded when presented in the output. 

The user is given the option of shifting the grid squares 
up to 2 ft in either the horizontal or vertical direction. This 
results in a new set of illumination values for that surface. 
This shifting of the grid squares can mean the difference 
between compliance and noncompliance on a particular sur- 
face. The following section presents the technique used to 
calculate the illumination values from a typical mining 
machine headlamp. 



Peak illumination 
direction 




Headlight 



Plane parallel to 
photometer face 



Mine surface 

Figure A-1 .—Illustration of peak illuminance measurement. 

Resultant peak 
Epeak luminoire 2 illuminance 




Plane parallel to 
photometer face 



Luminalre 2 



Mine surface 



Figure A-2.— Vector addition of illuminances. 



59 



ILLUMINATION CALCULATIONS— HEADLAMPS 



The following is an example of the equations used for 
computing the illuminance at a single selected location for 
a headlamp type luminaire. The same technique is used in 
the computer model. 

Definitions: 

The isofootcandle profile of a headlamp is defined and 
modeled as an ellipse of revolution as depicted at the dotted 
ellipse as shown in figure A-3. 

Origin, O, is defined as the center of the lens face of the 
headlamp. This point corresponds to the x,y,z location of 
the luminaire when it was positioned on the machine model. 
For this example O is set at (0,0,0) as shown in figure A-3. 

Measurement point, P, is defined as the location in the 
x,y,z field where illuminance is to be computed. (P x ,P y ,P z ) 
are the coordinates of point P. 

is defined as the angle between the line OP and the 
y-axis in the plane defined by the origin, O, point P, and 
the y-axis. is measured in degrees. 

Pj is defined as the intersection of the line OP and the 
surface of the eclipse of revolution. Typically, the isofoot- 
candle profile will be a 2.0-fc profile for mine luminaires, 
from which other field illuminance values can be derived 
using the inverse square law. 



2.0- fc 

isoilluminance profile 

(ellipse) 



0, origin 




P (Px'.py) 



Figure A-3.— Isoilluminance profile model for headlamps: 
ellipse model. 




>-P(Px,Py,Pz) 



Ellipse of revolution 
( isoilluminance profile) 



Primary beamdirecnon 

Figure A-4.— Isoilluminance profile model for headlamps: 
definition of (X', Y) coordinate system. 



Figure A-4 is the plane defined by the origin, O, point P, 
and the y-axis from figure A-3. 

The y-axis is defined as the axis of the primary beam (ATM 
vector) emitted from the headlamp as depicted in figure A-3. 

The isofootcandle profile of a headlamp is defined as an 
ellipse having a major axis, a, and a minor axis, b. The 
ellipse is tangent to the origin of the (x',y coordinate system 
as shown in figure A-4. The full profile is an ellipse of revolu- 
tion about the y' (also y) axis. 

Pi' is defined as the intersection of the 2.0-fc profile and 
a line joining the origin and point P'. 

Illuminance as measured by the MSHA STE method is 
defined as the footcandles impinging on a surface normal 
to the line OP. Note, therefore, that the cosine law of 
illumination is not used. 

The steps for computing the illuminance at point P are 

Step 1. Solve for 

Step 2. Solve for Pj' = (P x ', P y ') by solving for the in- 
tersection of the 2.0-fc profile and the line OP'. 

Step 3. Solve for the length of line OP/, in feet. 

Step 4. Using the inverse square law for illumination, 
solve for illuminance at P, which is the illuminance at point 
P in figure A-4. 

Some of the derivations for the following equations have 
been omitted. 



Step 1. Solve for 0: 


t(p x ) 2 + (P^y* 


Tan — 


(Py) 


= tan" 1 


" [ (P x f + (P^ ] 1/2 ' 


[ (Py) j 



Step 2. Solve for Pj = (P x ', P y '): 
x' = x' coordinate of point Pj' = 



2ab 2 



b 2 + (P y '/P X T a 2 
y' = y' coordinate of point Pj' = (P y 7P x ') x' 
Step 3. Solve for the length of line OPj, in feet: 
OPj = (x 2 + y 2 + z 2 ) 1/2 
OPj = [ (xT + (yT ] 1/2 



OPi = 


2ab 2 


. b 2 + (P y 7P x ?a 2 . 


Py' [G 


?J> + (P x f] 1/2 



+ Py'/Px' 



2ab 2 I 2 ] 1 

+ (P y 7P x ?a 2 J J 



Pv' 



therefore, 



OPj = 



= tan 0; 



2ab 2 



b 2 + a 2 tan 2 



2ab 2 tan 



b 2 + a 2 tan 2 



60 



2ab 3 



b 2 + a 2 tan 2 



[(p z y + (P x y] i/2 



or 

OP;= ) 

where 

tan 

Step 4. Solve for the illuminance at P: 

E = I/D 2 

Let D = OPi and E 2 = 2.0 fc. 

I = E 2 D 2 = E.COPi) 2 ; 

therefore, 

I = 2(OP i ) 2 



where I = beam intensity Guminous intensity) where the 
isofootcandle profile (2.0 fc) is given as an 
ellipse. 



Therefore, let E = illuminance at any field location P, as 
shown in figure A-4. 

By the inverse square law 

E(P x ,P y ,P z ) = 2(OP i ) 2 /(OP> = illuminance at any loca- 
tion (P^PyjP^ in coordinate 
system as shown in figure 
A-4, 



where 

OP= [(P x f + (P y ) 2 + (P^] 1 ' 2 , 



OPi = 



tan = 



2ab 2 



b 2 + a 2 tan 2 



[(P z f + (P^] 1 ' 2 



(1 + tan 2 0) 



61 



MAINTAINABILITY DESIGN OF MOBILE 
UNDERGROUND MINING EQUIPMENT 



By Ernest J. Conway 1 and Richard L. Linger 2 



ABSTRACT 



The Bureau of Mines has initiated a project to investigate the extent to which main- 
tainability design principles are used in the underground mining industry. This paper 
presents some of the preliminary findings from that work. 



INTRODUCTION 



Because of the persistently high number of mainte- 
nance-related injuries, new methods for reducing injuries 
and costs are being sought. One factor that contributes 
directly to injuries and costs is the design of the equipment 
itself. Cost-effective and safe maintenance can be achieved 
through improved equipment design for maintenance. 

To specifically address the design of underground min- 
ing equipment with respect to maintainability, the Bureau 
has entered into contract JO 145034 with Vreuls Research, 
Inc. The project is organized into two phases. Phase I tasks 



include a review of relevant maintainability design litera- 
ture, analysis of maintenance-related accident data, field 
reviews of equipment design in underground operating 
environments, and interviews with mine maintenance 
personnel and equipment manufacturers. 

A draft maintainability design guideline is being pre- 
pared based upon the findings of these tasks. Phase II tasks 
will focus on the field validation and revision of the design 
guidelines. This paper reviews the preliminary findings 
derived from phase I activities. 



PHASE I PRELIMINARY FINDINGS 



A review of the maintainability literature produced few 
specific guidelines that could be applied to underground 
mining equipment. However, a number of general engineer- 
ing and human factors design recommendations were found. 
Where practical, these findings were extrapolated for use 
in the underground environment (e.g., anthropometric 
measurements, reach envelopes, access opening sizes, etc.). 
Several design principles were found that may also be appli- 
cable. The plethora of maintainability models, however, 
appear to be of little practical value. 

Analysis of the injury data for underground mines 
indicates that maintenance-related accidents accounted for 
approximately 34 pet of all lost-time injuries (Mine Safety 
and Health Administration data). Approximately 29 pet of 
these injuries can be classified as serious, and they resulted 
in more than 1 day of lost time. 

Table 1 identifies types of serious (days lost >1) main- 
tenance-related injuries for two of the larger mines visited 



'Principal investigator, Vreuls Research, Inc., Westlake Village, CA. 
2 Civil engineer, Bureau of Mines, Pittsburgh Research Center, Pitts- 
burgh, PA. 



as part of this project. Overexertion and other injuries 
related to accessing, handling, installing, and removing 
machine components account for a majority of the reported 
injuries. Followup reviews of mining equipment at these 
sites suggested that many of these injuries were the direct 
result of current equipment design. 



Table 1.— Summary of serious (days lost >1) maintenance- 
related injuries for two mines 



Nature of injury 

Overexertion and strains while removing, replacing, or 

manipulating components 

Crushing, pinching, or laceration received while han- 
dling machine components 

Impacted by handtools or power tools or other metal 

parts during maintenance operation 

Lacerations and abrasions while working on equipment 
Slips and falls while working on or around equipment 
Other types of injuries 



Share of 

serious lost 

time injuries, pet 



36.4 



32.4 

11.5 
7.1 
5.4 
7.2 



62 



As expected, the data also revealed that a majority of 
the accidents resulted in less than 1 day of lost time. The 
injuries from these accidents included abrasions, contusions, 
sprains, burns, punctures, and similar types of trauma. In 
most of these cases, the mine personnel were returned to 
their jobs or assigned to light duty for a couple of days. These 
injuries often resulted from equipment design limitations 
such as limited access opening size, lack of guarding, im- 
proper tool design, and poor visibility while performing 
maintenance tasks. Personnel inattention and inexperience 
also contributed to these accidents. 

A number of crippling injuries and fatalities were also 
identified to be maintenance related. In several instances, 
equipment design may have directly or indirectly contrib- 
uted to these incidents. For example, one mine maintenance 
man was severely burned when he removed the cover to 
a power panel and proceeded to reattach a loose wire with- 
out first turning off the electric power to the box. An in- 
terlock switch on this panel cover might have prevented 
this accident. 

Field inspection of mining equipment revealed a num- 
ber of maintainability design problems and design limita- 
tions that were common to most categories of mobile equip- 
ment. Representative maintainability design problems 
include 

Lack of ability to visually inspect components for damage, 
leaks, or failures (fig. 1). 

Inadequate access opening size, preventing personnel from 
performing tasks with both hands or required tools, or 
preventing visual inspection of tasks being performed 
(fig. 2). 

Inadequate or no access openings for routinely performed 
inspections or maintenance actions. 

Need to remove or replace nonaffected components in 
order to access components actually being serviced (fig. 3). 

Lack of ability to secure, attach to, or lift heavy com- 
ponents during removal and replacement (fig. 4). 



Poor routing of hydraulic lines, water hoses, and power 
cables on the machine (fig. 5). 

Mounting of frequently serviced components in inacces- 
sible locations (fig. 6). 

Lack of check valves, stops, and other safety devices for 
servicing booms, heads, and other hydraulically activated 
systems. 

Design of components and maintenance procedures that 
require specialized tools and equipment not frequently 
found in operating mine sections. 

Failure to guard exposed components, hoses, valves, 
lights, and other high-maintenance items on equipment. 

Design of equipment bays and cavities that permit accu- 
mulation of mud, coal, and other debris that must be 
removed before maintenance can be performed (fig. 3). 

Interviews with mine management and maintenance 
personnel substantiate these findings. The consensus of the 
personnel interviewed was that the time required to per- 
form a specific maintenance task could be substantially 
reduced if simple maintainability design principles were 
to be applied to the design of mining equipment. In fact, 
personnel of 8 of the 10 mines visited during phase I 
reported that they have modified their equipment in order 
to improve maintainability. Inspection of the mining equip- 
ment itself revealed that at all 10 sites equipment had been 
modified in order to facilitate maintenance. 

A review of maintenance records substantiated the con- 
sensus. Maintenance data at one well documented mine 
maintenance operation revealed that 25 pet of all main- 
tenance personnel time was spent replacing hydraulic lines, 
water hoses, and power cables. The average time to remove 
and replace these items was 2.2 h per item. Examination 
of the equipment at this mine indicated that this removal- 
replacement time could be reduced to under 1 h if 25 pet 
of the hoses and cable fittings could be relocated to permit 
direct access. 



CONCLUSIONS 



The evidence collected to date suggests that substan- 
tial improvements in maintenance personnel safety and 
task performance times could be achieved if relatively sim- 
ple maintainability design principles were to be applied to 



the design of mining equipment. The objective for the 
remainder of this project is to prepare a maintainability 
design guideline to be used by mine personnel and 
manufacturers. 



63 




Figure 1.— In this example, many of the hydraulic components cannot be easily inspected for damage or leaks. 




Figure 2.— Inadequate access openings prevent visual inspection or the use of proper tools for making repairs. 



64 




Figure 3.— In order to replace the smaller motor, the larger motor and hydraulic tank must be removed. Also, the design of the 
trough allows for the accumulation of mud and coal around the components. 




Figure 4.— Massive components, such as this motor, should have designated lift points to facilitate removal and replacement. 



65 




Figure 5.— The closely packed routing of hydraulic and electrical lines makes even simple hose repair jobs a major task. 




Figure 6.— The simple task of replacing a headlamp can result in extra downtime when headlamps are installed in inaccessible 
locations. 



66 



ASSESSMENT OF ILLUMINATION FOR 
TASKS PERFORMED BY OPERATORS OF MOBILE SURFACE 

COAL MINING EQUIPMENT 



By Alan G. Mayton 1 



ABSTRACT 



This paper presents a portion of the results of an extensive Bureau of Mines study 
to assess the task illumination needs on mobile surface mining machinery. The intent 
of the research was to study these needs and the visibility requirements of machinery 
operators in performing visual tasks. Investigations were performed at 22 surface mining 
operations, coal and metal-nonmetal, within several mining regions of the United States. 
Visibility and illumination measurements were taken for 159 visual tasks on 57 sur- 
face mining machines including draglines, shovels, blasthole drills, bulldozers, loaders, 
haul trucks, graders, scrapers, and several service-type vehicles. This paper addresses 
only the results of investigations at surface coal mines; a subsequent Bureau report 
will present the overall results and recommendations of the entire study. Tables are 
presented that compare computed levels of luminance and illuminance for workers in 
the 25- and 50-yr-age groups. These tables show that illumination, and consequently, 
task visibility, could be improved. The paper also makes recommendations for 
improvements in illumination and/or task visibility. 



INTRODUCTION 



Since the Coal Mine Health and Safety Act became 
effective in 1969, the Bureau has had a major role in 
illumination research and in the development of illumina- 
tion criteria and technology to provide adequate lighting 
for workers in U.S. mining operations. This has been 
accomplished most notably in underground coal mining, and 
to an extent, in surface mining. 

In 1977, the Mining Enforcement and Safety Adminis- 
tration (MESA) under the Department of the Interior (now 
the Mine Safety and Health Administration (MSHA) under 
the Department of Labor) published proposed mandatory 
safety standards for the illumination of surface coal mines 
and surface work areas of underground coal mines (i). 2 

'Mining engineer, Pittsburgh Research Center, Bureau of Mines, Pitts- 
burgh, PA. 

2 Italic numbers in parentheses refer to items in the list of references 
preceding the appendix at the end of this paper. 



These standards, however, were never approved. In 1981, 
the International Commission on Illumination (CIE) began 
to focus attention on illumination standards for surface 
mining by establishing a working program for opencast 
(surface) mine lighting with the objective of developing 
recommendations for surface mine illumination. 

Concurrent with its involvement with the CIE and in 
view of the unapproved lighting standards, the Bureau 
initiated a program to study illumination on mobile sur- 
face mining equipment from the viewpoint of the equipment 
operators. The objective of the program was to assess the 
illumination needs of various surface mining equipment on 
the basis of the visibility required by workers in perform- 
ing the necessary visual tasks associated with their jobs. 
Moreover, the results of this study should provide useful 
data and information to establish lighting standards for 
surface mines. 



67 



OVERVIEW AND DESCRIPTION OF WORK 



The study was performed in accordance with methods 
and practices recommended by the CIE and the Illumi- 
nating Engineering Society of North America (IES). The 
approach essentially involved collecting visibility and 
illumination data through on-site visits to surface mines 
and quarries in various mining regions of the United States. 
Investigations took place at 22 different surface mining 
operations located in Michigan, Indiana, Alabama, Florida, 
Ohio, Massachusetts, New Hampshire, and New York; 15 
were metal-nonmetal (MNM) quarries and 7 were coal 
mines. The MNM operations included two iron ore mines, 
four phosphate mines, seven limestone quarries, and two 
granite quarries. Visual tasks were identified for equipment 
operators on 57 surface mining machines and quarry equip- 
ment including draglines, shovels, blasthole drills, 
bulldozers, loaders, haul trucks, graders, scrapers, lubrica- 
tion trucks, fuel trucks, and a water truck. Visibility 3 was 
measured for 159 tasks with a Blackwell 4 model 5 visual 
task evaluator (VTE). Existing illumination for each task 
was determined by using a Minolta 1 ° luminance meter. 

Although the study included both surface coal and MNM 
mining, this paper will concern only surface coal mining. 
A subsequent report will address the overall study and will 
discuss, in detail, the procedures and results. 



or "optical fog." The point at which the critical detail of 
the task can be seen just barely through the intervening 
optical fog is called threshold. The proportion of the original 
contrast perceived through the instrument's optics is called 
the contrast transmittance (CT) of the instrument. The CT 
varies from almost 100 pet to almost zero as the background 
luminance remains nearly constant (4). 

A measure of how well a given target can be seen is 
expressed in the amount of reduction in task contrast that 
is needed to bring the detail to threshold. If, for example, 
a given target object reaches visibility threshold at a value 
of CT equal to 0.10, the target is inherently 10 times above 
its threshold value. The target is said to have a relative 
visibility level (VL) of 10. A measure of relative visibility 
for objects is determined mathematically by taking the 
reciprocal of the contrast transmittance; i.e., VL= 1/CT. 
Thus, scenes that are highly visible will require more con- 
trast reduction to reach visibility threshold, while those that 
are moderately visible will require less (4-5). 

Further, measuring task visibility with the VTE 
requires that the operator of the VTE go through a specific 
calibration procedure. This procedure is explained in the 
Bureau report that will present the overall results and 
recommendations of the study. 



CIE-IES METHOD 



FIELD MEASUREMENTS 



The use of the VTE to obtain visibility measurements 
is based on the CIE-IES method, which compares an actual, 
real-world visual task to a standard, visibility reference 
task. The task consists of an observer viewing a luminous 
disk whose diameter subtends 4' of arc at the observer's eyes 
when presented in a series of 0.2-s exposures on a task 
background of uniform luminance. Moreover, the visibility 
reference task is the basis for the visibility reference func- 
tion, which represents visibility threshold values obtained 
by a 20- to 30-yr-age reference observer (2). A detailed 
explanation of this method is contained in reference 3. 



BLACKWELL MODEL 5 VTE 

The Blackwell model 5 VTE operates by allowing one 
to vary the visual contrast of objects seen through the 
instrument by fading out the luminance of a scene while 
at the same time introducing a uniform veiling luminance, 



'Visibility and illumination data resulting from investigations at the two 
granite quarries and one limestone quarry were not included because the 
VTE was later found to be out of calibration. Also, it was not possible to 
obtain visibility measures at the phosphate mines and one other limestone 
quarry. 

'Reference to specific products does not imply endorsement by the Bureau 
of Mines. 



After selecting a visual task, the VTE was set up in the 
location from which the operator would normally view the 
task. The approximate angular position of the VTE and the 
approximate distance from the outer lens of the VTE to the 
object or surface of interest were measured or estimated and 
then recorded. The proper outer lens unit was selected based 
on the recorded distance and was attached to the front of 
the VTE. While looking through the VTE, the operator 
adjusted the contrast control dial on the side of the instru- 
ment to threshold contrast no fewer than five times and the 
readings were recorded. The luminances of the target and 
its background were then measured with the Minolta meter. 
The illuminance or illumination of the task was determined 
from the luminance measured for a reflectance standard, 
the RS-1 plaque (reflectance approximately 100 pet), which 
was placed on or directly above the target. In addition, 
Munsell charts were used where needed to determine the 
reflectance of surfaces of interest. Slide photographs were 
also taken of the illuminated equipment and the detail of 
each task. 

The data collected from field measurements were subse- 
quently tabulated, adjusted to take into account the dif- 
ference in the visual conditions of the model 5 VTE relative 
to single glimpse conditions used in reference 3, and then 
analyzed according to the indirect method contained in 
reference 3. Representative results of the data analysis 
appear in the appendix tables at the end of this paper. 



68 



CONCLUSIONS AND RECOMMENDATIONS 



This study shows that the type and extent of illumina- 
tion does vary from mine to mine and seems to be influ- 
enced by several factors including mine size, tonnage, and 
management philosophy. Although the operators of surface 
mines and quarries, in general, have made positive strides 
toward providing adequate machine lighting, there are 
instances where the lighting and/or visibility for certain 
visual tasks could be improved. 

One example involves the power cable on draglines or 
shovels, which must be handled when relocating these 
machines. Because the cable is frequently dragged along 
the ground during these procedures, the cable can become 
discolored so that it blends with the surface of the ground. 
The visibility of the power cable in this case could be 
improved by applying material such as reflective tape to 
increase the cable's contrast as seen against its background. 

Another example is the need for improving visibility and 
illumination on dozers and loaders in viewing areas 
immediately ahead of the machines, and areas adjacent to 
either end of the blade or bucket. Improvements in these 
areas can be made by (1) assuring the proper aiming of 
luminaires and/or (2) replacing existing lamps with those 
of higher intensity. 



Two other examples involve machinery working near 
the highwall of the mining pit. A principal danger 
associated with the highwall is the potential for rocks and 
other material to fall or roll off these nearly vertical walls 
of overburden. The danger in dump areas is the potential 
for haul trucks to topple over the edge of the pit when dump- 
ing waste material. Illumination levels can be increased and 
the required visibility attained in these cases by using 
portable light plants. The light plants, however, should be 
placed in locations that would minimize glare for equipment 
operators. 

Finally, the use and application of the instrumentation 
and methods presented in this paper may help a surface 
mining company to improve its existing levels of luminance 
and illuminance on and immediately about its mining 
equipment. Further, the tables in the appendix show the 
results of calculations based on the field data. Because of 
the wide variation in machine lighting, the limited time 
available to take measurements on operating equipment, 
and the limitations of the instruments used, the data given 
in the tables are only indications of the luminances, 
illuminances, and reflectance factors needed to perform the 
various visual tasks. 



REFERENCES 



1. Federal Register. U.S. Mining Enforcement and Safety Admin- 
istration (Dep. Interior). Illumination. V. 2, No. 9, Jan. 13, 1977, 
pp. 2805-2807. 

2. Hitchcock, L.C. Development of Minimum Luminance Re- 
quirements for Underground Coal Mining Tasks (contract 
H0111969, U.S. Dep. of Navy). BuMines OFR 12-74, 1973, 288 pp.; 
NTIS PB 230 447. 

3. Commission Internationale de l'Eclairage (CIE), Technical 
Committee 3.1 (Paris). An Analytical Model for Describing the 



Influence of Lighting Parameters Upon Visual Performance. 
Volume 1, Technical Foundations; Volume 2, Summary and 
Application Guidelines. CIE Publ. 19/2 (TC-3.1), 1981, 235 pp. 

4. Merritt, J.O., T.J. Perry, W.H. Crooks, and J.E. Uhlaner. 
Recommendations for Minimal Luminance Requirements for Metal 
and Nonmetal Mines (contract J0318022, Perceptronics, Inc.). 
BuMines OFR 65-85, 1983, 236 pp.; NTIS PB 85-215689. 

5. Kaufman, J.E. (ed.). IES Lighting Handbook. Illuminating 
Eng. Soc, 1981, 577 pp. 



69 



APPENDIX.— RESULTS OF TASK VISIBILITY MEASUREMENTS 



The tables of data presented should not be construed as 
absolute, but should be used as a general guide to help in 
better understanding the illumination needs of machinery 
operators at surface mines. Also, note the following regard- 
ing the data: 

Values appearing under the column headings "Computed 
luminance" and "Computed illuminance" were calculated 
for the median age in each group; i.e., the average 25- and 
50-yr-age groups of the normal population. 

Computed values of luminance and illuminance were 
rounded, for consistency, after the calculations were made. 

Variations in luminances and illuminances for similar 
tasks and equipment are largely the result of the wide dif- 



ferences in conditions under which field measurements were 
taken. 

In general, the visual task with high contrast between 
the task target or critical detail and its background, will 
result in good visibility and relatively lower illuminance 
levels; conversely, the visual task with low contrast will 
result in poorer visibility and relatively higher levels of 
illuminance. 

The footnote "Supplemental lighting" refers to illumina- 
tion added to the scene for certain visual tasks (generally 
in the direction of normal or existing lighting) to increase 
the transmittance through the VTE. 



Table A-1 .—Illumination values resulting from task visibility measurements for coal mine draglines 



Computed 
luminance, fl_ 



Existing 

illuminance, 

fc 



Viewing 

distance, 

ft 



20- to 
30-yr 
age 



40- to 
60-yr 
age 



Reflectance, 
pet 



Computed 
illuminance, fc 



20- to 
30-yr 
age 



40- to 
60-yr 
age 



DRAGLINE 1 



SEEN FROM— 
Operator's cab: Tooth of bucket resting on ground 5.11 

SEEN FROM— 

Operator's cab: 

Top of spoil pile 1 2.40 

Lower edge of bucket on slope of pit 1 1.38 

Coal with respect to overburden 1 1 .34 

Dump block on hoist rope 1 2.10 

Ground level at rear of machine: Power cable 1.31 

SEEN FROM— 

Operator's cab: 

Control panel button 9.24 

Tooth of bucket resting on ground 1 .27 

Landing: Landing edge to stairs 3.48 

1 Extrapolated from other measurements. 



100 



0.058 0.095 



9.00 



3.10 



5.13 



DRAGLINE 2 



150 


0.036 


0.058 


2.08 


1.74 


2.80 


105 


.371 


.743 


47.10 


.79 


1.58 


150 


1.18 


2.99 


14.18 


8.34 


21.11 


150 


.039 


.063 


2.86 


1.36 


2.19 


3.7 


2.22 


6.86 


9.92 


22.40 


69.17 



DRAGLINE 3 



1.8 

24.1 

4.7 



0.037 

1.121 

.014 



0.060 

2.193 

.022 



34.52 

18.90 

3.45 



0.11 

5.94 

.41 



0.17 

11.61 

.61 



Table A-2.— Illumination values resulting from task visibility measurements for coal mine shovels 



Computed 
luminance, fL 



Existing 

illuminance, 

fc 



Viewing 

distance, 

ft 



20- to 
30-yr 
age 



40- to 
60-yr 
age 



SEEN FROM— 

Operator's cab: 

Top rear edge of loaded dipper 1 1.40 

Top edge of empty truck bed 11 .20 

Top edge of truck bed loaded M.SO 

Height of load in truck 1 1.70 

Ground level at rear of machine: Power cable .23 

ipper ' 

ndhoid : 

1 Extrapolated from other measurements. 



Reflectance, 
pet 



Computed 
illuminance, fc 



20- to 
30-yr 
age 



40- to 
60-yr 
age 



SHOVEL 1 


SEEN FROM— 
Operator's cab: Rear edge of dipper rest' 


ng on 


ground . . . 


6.84 


28 


0.381 


0.765 


16.52 


2.31 


4.63 


SHOVEL 2 


SEEN FROM— 
Operator's cab: 
Rear edge of bulldozer 






1.41 

.70 

2.00 


50 
25 
24.6 


0.038 
.251 
.80 


0.061 
.478 
.139 


4.26 
10.00 
10.00 


0.89 

2.52 

.80 


1 43 


Rock on slope of bench highwall 






4.78 


Rear edge of dipper resting on ground 






1.39 


SHOVEL 3 



30 


0.240 


0.453 


10.00 


2.40 


4.53 


20 


.062 


.103 


10.00 


.62 


1.03 


25 


.513 


1.08 


34.62 


1.48 


3.12 


30 


.045 


.074 


1.76 


2.58 


4.20 


3.5 


.020 


.031 


17.39 


.12 


.63 



SHOVEL 4 


SEEN FROM— 
Operator's cab: Top rear edge of loaded dipper 


1 12.60 25 


1.30 


3.39 


10.00 


13.06 


33.91 


SHOVEL 5 


SEEN FROM— 
Ground level at rear of machine: 

Bottom rung of boarding ladder 

Fifth rung of boarding ladder used as handhold 


2.09 2.3 
2.83 1.3 


0.140 
.003 


0.248 
.005 


12.92 
.71 


1.08 

.46 


1.92 
.66 



70 



Table A-3.— Illumination values resulting from task visibility measurements for coal mine loaders 



Existing 

illuminance, 

fc 



Viewing 

distance, 

ft 



Computed 
luminance, fL 

20- to 40- to 
30-yr 60-yr 
age age 



Reflectance, 
pet 



Computed 
illuminance, fc 



20- to 
30-yr 
age 



40- to 
60-yr 
age 



LOADER 1 



SEEN FROM— 
Ground level at boarding ladder: 

Bottom step 

Handrail 

Plate-metal landing outside operator's cab 

Handrail 

Edge of landing to descending ladder . . 
Operator's cab: Height of load in bucket. . 

SEEN FROM— 
aerator's cab: Left end of bucket .... 

SEEN FROM— 
aerator's cab: Top rear edge of loaded 

1 Extrapolated from other measurements 



1 0.78 
1 .02 

1.01 
.39 
.37 



2.3 
1.4 

1.4 
3.6 
15 



0.017 
.016 



0.026 
.024 



.017 .026 

.068 .114 

.031 .050 



1.28 
50.00 

1.98 
10.26 
10.81 



1.33 
.03 



2.06 
.05 



.86 1.33 

.66 1.11 

.29 .46 



LOADER 2 


SEEN FROM— 
Operator's cab: Left end of bucket 


2.65 15 


0.028 


0.046 


1.89 


1.51 


2.41 








LOADER 3 


SEEN FROM— 
Operator's cab' Top rear edge of loaded bucket 


8.78 13 


0.162 


0.294 


17.08 


0.95 


1.72 









Table A-4.— Illumination values resulting from task visibility measurements for coal mine haul trucks 



Computed 
luminance, fL 



Existing 

illuminance, 

fc 



Viewing 

distance, 

ft 



20- to 
30-yr 
age 



40- to 
60-yr 
age 



Reflectance, 
pet 



Computed 
illuminance, fc 



20- to 
30-yr 
age 



40- to 
60-yr 
age 



TRUCK 1 



SEEN FROM— 
Driver's cab: 

Edge of ditch 

Pile of debris in front of truck 

Ground level at boarding ladder 

SEEN FR 
3 at dump 

SEEN FR 

iste dump 2 
ir 

SEEN FR 

Darding lad 

sscending) 

SEEN FROM— 
Driver's cab: 2 

Tire track at loading shovel 3 

Sloped waste pile at base of bench highwall 3 

Rear (shadowed) edge of loading shovel 3 

1 Supplemental lighting required to make measurements 



0.50 
.54 



130 
55 



0.107 
.018 



0.186 
.029 



14.81 
1.85 



0.72 
1.00 



1.25 
1.55 



Bottom step 


11.21 




2.2 
1.3 


.018 
.043 


.028 
.070 


1.65 
8.20 


1.1.0 

.53 


1.71 


Handbar 


i.61 


.85 


TRUCK 2 


SEEN FROM— 
Driver's cab: Left curb at dump hopper 


1 .02 




35 


0.620 


1.37 


6.86 


9.04 


19.97 








TRUCK 3 


SEEN FROM— 
Driver's cab: 
Edge of berm at waste dump 2 


0.91 




32.5 
3 


0.025 
.069 


0.041 
.115 


1.10 
6.45 


2.27 
1.08 


3.71 


Body-down indicator 


1.31 


1.78 








TRUCK 4 


SEEN FROM— 
Landing at head of boarding ladder: 

Handrail of landing 

Edge of landing (descending) 


0.10 

.54 




1.8 
3.6 


0.022 
.016 


0.035 
.026 


20.00 
1.80 


0.11 
.89 


0.18 
1.45 








TRUCK 5 



3.15 


99.3 


0.432 


0.886 


8.89 


4.86 


9.97 


1.48 


138 


.198 


.367 


1.35 


14.67 


27.18 


1.90 


99.3 


.781 


1.78 


10.00 


7.81 


17.80 



2 Left, side-view mirror used. Positioning and/or maneuvering mark. 



71 



Table A-5.— Illumination values resulting from task visibility measurements for coal mine blasthole drills 



Existing Viewing 

illuminance, distance, 

fc ft 



Computed 
luminance, fL 

20- to 40- to 
30-yr 60-yr 
age age 



Reflectance, 
pet 



Computed 
illuminance, fc 



20- to 
30-yr 
age 



40- to 
60-yr 
age 



DRILL 1 



SEEN FROM— 
Operator's cab: 
Shovel (marker) to align machine for drilling next hole 

Stem lock against drill pipe 

Paint mark on hoist chain 



27.24 60 
15.10 8 

16.53 12 



0.226 0.423 
.128 .227 

.081 .137 



SEEN FROM— 
Operators cab: 
Edge of box (marker) to align machine for drilling 

next hole 1 .43 

Edge of deck bushing against drill pipe 9.18 

Rope with weighted end for spacing holes 1 23.30 

Ground level at operator's cab: Boarding step 2.16 

SEEN FROM— 

Operator's cab: 

Edge of deck bushing without drill pipe 2.14 

Edge of pipe rack against drill pipe 4.43 

Ground level at boarding stairs: 

SEEN FROM— 
Operator's cab: 

Edge of deck bushing against drill pipe 1.48 

Mark on hoist cable .93 

Drop pin in drill pipe carousel 55 

Point of pressure gauge 6 

Small hole in deck 2.85 

Supplemental lighting required to make measurements. 



21 

4.5 
20 
4.5 



0.568 
.533 
.336 
.028 



1.22 
1.13 
.663 
.045 



16.52 

4.44 

15.12 



6.99 
5.45 
4.25 
4.63 



1.37 

2.89 

.54 



8.12 

9.78 

7.91 

.60 



2.56 

5.11 

.91 



DRILL 2 


SEEN FROM— 
Landing at head of boarding ladder: 
Edge of landing to descending stairs 


2.40 




3.7 


0.063 


0.106 


4.17 


1.52 


2.55 


DRILL 3 


SEEN FROM— 
Operator's cab: Point of pressure gauge 


11.51 




1.5 


0.012 


0.018 


56.95 


0.02 


0.03 








DRILL 4 



17.45 

20.71 

15.61 

.96 



DRILL 5 



0.147 
.091 



0.262 
.156 



2.34 
10.38 



6.27 
.88 



11.21 
1.50 



Bottom step 


4.50 




2.1 
1.8 


.032 
.095 


.051 
.163 


8.22 
8.40 


.38 

1.13 


.62 


Handrail 


1.31 


1.94 


DRILL 6 



5 


0.304 


0.588 


25.00 


1.22 


2.35 


4.3 


.029 


.041 


13.98 


.65 


1.00 


6 


.790 


1.81 


21.82 


3.62 


8.30 


1.4 


.616 


1.35 


62.17 


.99 


2.17 


4 


.458 


.948 


32.28 


1.42 


2.94 



Table A-6.— Illumination values resulting from task visibility measurements for coal mine explosive trucks 



Computed 
luminance, fL 



Existing 

illuminance, 

fc 



Viewing 

distance, 

ft 



20- to 
30-yr 
age 



40- to 
60-yr 
age 



Reflectance, 
pet 



Computed 
illuminance, fc 



20- to 
30-yr 
age 



40- to 
60-yr 
age 



TRUCK 1 



SEEN FROM— 
Ground level at rear of truck: 

Edge of bagged explosives 

Detonating cord against primer 

Hole slot in primer 

Black digit on tape measure 

SEEN FROM— 
Ground level at rear of truck: Edge of blasthole 

'Supplemental lighting required to make measurements. 



1.84 

2.30 

2.28 

20.70 



3 

1.3 
1.3 
4.3 



1 .04 2.53 
.188 .347 

.258 .493 

.718 1.62 



29.35 

27.83 

32.46 

9.90 



3.54 
.68 
.79 

7.25 



8.64 

1.25 

1.52 

16.37 



TRUCK 2 



'150 



4.5 



0.312 0.612 



9.93 



3.14 



6.16 



72 



Table A-7. — Illumination values resulting from task visibility measurements for coal mine scrapers 

Computed 
luminance, fL 

Existing Viewing 20- to 40- to 

illuminance, distance, 30-yr 60-yr Reflectance, 

fc ft age age pet 

SCRAPER 1 
SEEN FROM— 

Operator's cab: 

Cutting edge of pan 1.96 16 2.15 6.49 18.88 

Pothole in road .77 39.6 .635 1.40 20.78 

Rock on road .45 47 1 .47 3.97 17.78 

Top rear edge of loaded pan 1 8.20 14 .204 .378 9.76 

Ground level at rear push bumper: 

Boarding step 2 12.24 2 .012 .019 2.53 

Handbar for boarding 21.79 1.3 .776 1.79 14.52 

SCRAPER 2 
SEEN FROM— 
Operator's cab: Cutting edge of pan 54.0 19 0.028 0.046 12.52 

'Extrapolated from other measurements. Supplemental lighting required to make measurements. 



Computed 
illuminance, fc 

20- to 40- to 
30-yr 60-yr 
age age 



1 1 .40 34.39 

3.06 6.74 

8.26 22.32 

2.09 3.87 



.49 
5.34 



0.23 



.76 
12.30 



0.36 



Table A-8.— Illumination values resulting from task visibility measurements for coal mine bulldozers 



Existing 

illuminance, 

fc 



Viewing 

distance, 

ft 



Computed 
luminance, fL 

20- to 40- to 
30-yr 60-yr 

age age 



Reflectance, 
pet 



Computed 
illuminance, fc 

20- to 40- to 
30-yr 60-yr 
age age 



BULLDOZER 1 



23 
16 



SEEN FROM— 
Operator's cab: 

Dirt at left blade end 0.80 

Dirt above blade when pushing load 135.70 

SEEN FROM— 

Operator's cab: Dirt at right blade end 1.56 

Ground level: 

bove tru 

inion ar 

ib: Pow 

SEEN FROM— 

Ground level: 

Edge of bottom at boarding ladder 0.06 

Handhold (rung) .03 

Operator's cab: Top edge of blade against load pushed . . 42.65 

SEEN FROM 
blade end age 

SEEN FROM 
blade end age 

SEEN FROM 
blade end ags 

SEEN FROM 
of machine: 
tep) for boardi 

SEEN FROM 
linst muddy lo 

SEEN FROM— 

Operator's cab: Top of blade against load pushed 6.35 

Ground level at boarding ladder: 
Bottom rung '36.80 

Handhold (rung) 1 .32 

BULLDOZER 11 
SEEN FROM— 
Operator's cab: 

Left blade end against ground surface 1.39 

Top, right blade end against ground surface 3.26 

Edge of deck outside door of cab 1 .33 

Ground level: 

Edge of trunion arm (step) for boarding .39 

Handbar above trunion arm for boarding .93 

'Supplemental lighting required to make measurements. 



0.054 0.088 
.002 .003 



1.25 
.02 



4.32 
10.00 



7.05 
15.00 



BULLDOZER 2 



20 



0.063 0.014 



13.3 



2.5 
1.3 



0.132 



.008 
.057 



0.234 

.012 
.093 



1.92 



8.66 

.46 
61.36 



3.26 



1.52 

1.78 
.09 



5.43 



Handbar above trunion arm for boarding 

Edge of trunion arm step for boarding 


.41 1.6 
.44 1.6 


2.96 
.021 


10.27 
.033 


34.15 
4.54 


8.65 
.46 


30.09 
.72 


BULLDOZER 3 


SEEN FROM— 
Operator's cab: Power cable of dragline 


0.47 42.2 


0.492 


1.03 


21.28 


5.25 


11.00 








BULLDOZER 4 



2.1 


0.018 


0.028 


16.67 


0.11 


0.17 


1.4 


.086 


.146 


100.0 


.09 


.15 


14 


.421 


.864 


4.99 


8.43 


17.30 



BULLDOZER 5 


SEEN FROM— 
Operator's cab: Left blade end against load pushed .... 


0.86 15 


0.325 


0.637 


30.23 


1.08 


2.11 


BULLDOZER 6 


SEEN FROM— 
Operator's cab: Left blade end against load pushed .... 


'122.40 15.6 


0.085 


0.145 


3.34 


2.54 


4.34 


BULLDOZER 7 


SEEN FROM— 
Operator's cab: Left blade end against load pushed .... 


M2.60 15.3 


0.188 


0.344 


23.81 


0.79 


1.45 


BULLDOZER 8 


SEEN FROM— 
Ground level at rear of machine: 
Edge of grouzer (step) for boarding 


'42.20 2.1 


0.001 


0.002 


0.02 


5.00 


10.00 


BULLDOZER 9 


SEEN FROM— 
Operator's cab: 
Left blade end against muddy load pushed 


1.51 17.5 


0.035 


0.056 


4.64 


0.76 


1.20 






BULLDOZER 10 



2.70 



2.57 
.15 



14.8 

14.5 

3.3 


0.572 
.081 
.200 


1.23 
.138 
.368 


17.27 

8.28 

32.33 


3.31 
.98 
.62 


7.12 
1.67 
1.14 


1.7 
2.8 


.010 
.005 


.015 
.007 


2.56 
2.15 


.39 

.23 


.60 

.35 



73 



Table A-9.— Illumination values resulting from task visibility measurements for coal mine motor graders 



Existing 

illuminance, 

fc 



Viewing 

distance, 

ft 



Computed 
luminance, fl_ 

20- to 40- to 
30-yr 60-yr 
age age 



Reflectance, 
pet 



Computed 
illuminance, fc 



20- to 
30-yr 
age 



40- to 
60-yr 
age 



GRADER 1 



SEEN FROM— 
Operator's cab: 

Pothole in road 

Top of windrow at right blade end . 

Top of left blade end 

Rock on road 

Clumped dirt at right blade end . . . 
Ground level at boarding ladder: 



10.31 
1.04 
6.26 
.44 
1.35 



85 

14.6 

10.7 

65 

14.7 



2.57 
.106 
.014 
.492 

5.41 



8.43 
.184 
.021 

1.03 
25.76 



SEEN FROM— 

Operator's cab: 

Left blade end 5.63 

Right blade end 7.23 

Ground level at boarding ladder: Bottom step 2.74 



13.4 
9.4 
1.9 



0.014 0.021 
.123 .216 
.320 .625 



29.03 

4.81 

.96 

22.73 

28.15 



1.06 

14.38 

5.84 



8.84 
2.20 
1.46 
2.16 
19.20 



1.30 

.86 

5.48 



29.05 
3.82 
2.16 
4.53 

91.51 



Bottom rung 

Handbar 


1.63 1.9 

1.11 1.4 


.024 
.009 


.037 
.014 


4.76 
9.09 


.50 
.10 


.78 

.15 


GRADER 2 



2.02 

1.50 

10.70 



GRADER 3 



SEEN FROM— 

Operator's cab: 

Right blade end 2.99 

Bottom of left blade end 1 .23 

Top of left blade end 1 .23 

Ground level at boarding ladder: Bottom step .36 



13.3 
8.7 
7.8 
2 



0.008 0.012 

.007 .010 

.027 .043 

.041 .067 



0.67 

.81 

7.32 

22.22 



1.14 
.87 
.37 
.18 



1.76 

1.23 

.58 

.30 



GRADER 4 



SEEN FROM— 
Operator's cab: 

Right blade end 

Left blade end 

Ground level at boarding ladder: Bottom step 

Supplemental lighting required to make measurements. 



2.26 
2.45 
1.67 



9 
13.4 
1.7 



0.012 0.019 
.080 .135 

.052 .085 



1.33 
5.31 
4.19 



0.94 
1.50 
1.23 



1.45 
2.54 
2.02 



Table A-10.— Illumination values resulting from task visibility measurements for coal mine fuel trucks 



Computed 
luminance, fL 



Computed 
illuminance, fc 



Existing 

illuminance, 

fc 



Viewing 

distance, 

ft 



20- to 
30-yr 
age 



40- to 
60-yr 
age 



Reflectance, 
pet 



20- to 
30-yr 
age 



40- to 
60-yr 
age 



TRUCK 1 



SEEN FROM— 

Ground level: 

Black digit of fuel meter 10.58 

Boarding step of cab 1 .30 

Handbar for boarding 1 1 .65 

Corner of walkway behind driver's cab: 
Edge of walkway along fuel tank 1.24 



2.3 
2.7 
1.3 

4.6 



0.109 
.038 
.026 

.007 



0.190 
.061 
.041 

.010 



8.62 

13.33 

6.67 

4.17 



1.27 
.29 
.39 

.17 



2.20 
.46 
.62 

.25 



TRUCK 2 



SEEN FROM— 
Ground level: 

Black digit of fuel meter 

Nozzle of fuel hose 

Boarding step of cab 

Supplemental lighting required to make measurements. 



1.70 


1.3 


0.178 


0.325 


7.03 


2.54 


4.63 


M.02 


1.5 


.167 


.304 


17.65 


.95 


1.72 


11.03 


3 


.010 


.015 


.97 


1.03 


1.59 



74 



Table A-1 1.— Illumination values resulting from task visibility measurements for coal mine lubrication trucks 



Existing 

illuminance, 

fc 



Viewing 

distance, 

ft 



Computed 
luminance, fL 

20- to 40- to 
30-yr 60-yr 
age age 



Reflectance, 
pet 



Computed 
illuminance, fc 



20- to 
30-yr 
age 



40- to 
60-yr 
age 



TRUCK 1 



SEEN FROM— 
Ground level at rear of truck: 

Tool in tool box 1 1 .21 

Nozzle of grease hose ' 12.80 

Chain link of boarding step 1 358 

SEEN FROM— 
Ground level at grease fitting of haul truck wheel: 
Nozzle of grease hose n 31 4 

SEEN FROM— 
Ground level: 

Nozzle of grease hose 1 33.2 

Boarding step of cab 1 1 .1 9 

Handbar for boarding 1 1 .63 

'Supplemental lighting required to make measurements. 



1.3 

2 

3.5 



0.054 0.089 
.029 .046 

.064 .108 



9.09 

9.22 

.22 



0.59 0.98 

.32 .50 

29.32 49.02 



TRUCK 2 



2.1 



0.040 0.064 



6.30 



0.63 1 .02 



TRUCK 3 



1.6 


0.068 


0.114 


3.46 


1.96 


3.28 


2 


.022 


.035 


9.24 


.24 


.38 


1.5 


.004 


.006 


3.07 


.13 


.19 



Table A-1 2. — Illumination values resulting from task visibility measurements for coal mine water truck 



SEEN FROM— 
Operator's cab: 

Vertical stream of water at fill-up point 

Top of berm at right side of road 

Water-filled pothole 

Rock on road 

Ground level at boarding ladder: 

Bottom rung 

Handhold (rung) 

'Supplemental lighting required to make measurements. 







Computed 




Computed 




Viewing 


luminance, fL 




illumin 
20- to 


ance, fc 


Existing 


20- to 


40- to 


40- to 


illuminance, 


distance, 


30-yr 


60-yr 


Reflectance, 


30-yr 


60-yr 


fc 


ft 


age 


age 


pet 


age 


age 


0.94 


117 


0.103 


0.177 


5.32 


1.93 


3.33 


.69 


88 


.009 


.013 


1.45 


.61 


.92 


1.13 


110 


.104 


.181 


5.31 


1.97 


3.40 


.64 


110 


.103 


.177 


7.81 


1.31 


2.27 


'2.04 


2.5 


.016 


.025 


.98 


1.66 


2.57 


M.81 


1.3 


.181 


.330 


11.05 


1.64 


2.98 



75 



ANALYSIS OF MAINTENANCE AND REPAIR ACCIDENTS 

ON HAULAGE TRUCKS 



By Thomas J. Albin 1 and Dennis A. Long 2 



ABSTRACT 

The Bureau of Mines analyzed metal and nonmetal surface mining maintenance 
accidents for a selected group of mining machines including haulage trucks, draglines, 
power shovels, and hydraulic excavators. The overall incidence rate of accidents has 
declined from 6.91 injury accidents per 200,000 h in 1978 to 4.34 injury accidents per 
200,000 h in 1985; however, maintenance accident incidence has remained approxi- 
mately constant. The severity of these maintenance accidents remains a serious prob- 
lem, with an average of 189 days lost, including statutory days assessed. 

Analysis of accident statistics in the Mine Safety and Health Administration data 
base shows that the predominant types of injury accidents, in terms of frequency and 
severity, are caught, hit-by, falls, overexertion, and electric shock. 

Further analysis was conducted as to the most hazardous subsystems of haulage 
trucks. Maintenance accident records involving off-road haulage trucks provided infor- 
mation regarding the particular subsystem worked on at the time of the accident. 
Maintenance times for haulage trucks, by subsystem, were obtained from a surface iron 
mine. The incidence rate and severity of accidents on any particular subsystem were 
then compared to the amount of time spent working on that subsystem relative to the 
total time spent in maintenance activity. 

Statistically, maintenance of the cooling subsystem, suspension, and tires all have 
accident rates that are significantly greater than accident rates on the other truck 
subsystem. 



INTRODUCTION 



Maintenance and repair accidents have been identified 
as a matter of serious concern to the surface mining industry 
(i). 3 This paper presents a condensed, preliminary analysis 
of mobile equipment maintenance and repair injuries and 
discusses injury prevention in the surface metal and 
nonmetal mining industry. 

The principal source of accident data used in this paper 
is the mine accident data file maintained by the Mine Safety 
and Health Administration (MSHA) at its Denver Safety 
and Health Technology Center. The data were utilized with 
the aid of the Bureau's accident data analysis (ADA) pro- 
gram. It is important to note that this program (2) defines 
an accident as "any unforeseen or uncontrolled occurrence 
which shuts down a face or work area for 30 minutes or 
more, whether or not an injury was sustained." A report- 
able injury is defined by MSHA (3) as an "injury to an 
individual that requires medical treatment or results in 
death or loss of consciousness or inability to perform all job 



'Industrial engineer. 
"Mining engineer. 

Twin Cities Research Center, Bureau of Mines, Minneapolis, MN. 
'Italic numbers in parentheses refer to the list of references preceding the 
appendix at the end of this paper. 



duties on any workday after the injury or temporary assign- 
ment to other duties or transfer to another job." 

The scope of this study is restricted to accidents in which 
injuries have occurred while the individual concerned was 
actually engaged in maintenance or repair of one of the 
specified machines, that is, a haul truck, dragline, power 
shovel, or hydraulic excavator. 

In addition to the number of accidents (frequency), two 
other measures of accident occurrence are used in this study: 
severity and incidence rate. In discussing the severity of 
injuries resulting in time lost from work, severity will be 
defined (2) as 

[days off work + statutory days + (0.5 day restricted)]. 

Statutory days are assessed according to the schedule of 
accident severity; e.g., a fatality results in a charge of 6,000 
statutory days against the employer. 

Accident incidence rates provide a means for comparing 
the relative frequency with which an accident or accidents 
occur in two or more populations that have different levels 
of exposure to a given hazard or hazards. Accident incidence 
rates allow comparisons between the populations based on 



76 



equivalent data. It is usually expressed as the number of 
accidents divided by the number of hours worked: Because 
accidents are relatively rare events, this ratio may be quite 
small. By convention, mining accidents are usually ex- 



pressed as the number of accidents per 100 workers per 
year: 

(number of accidents x 200,000)/(total hours worked in 1 yr). 



ACCIDENT INCIDENCE RATES 



As noted, accident incidence rates are expressed as the 
ratio of number of accidents occurring within a population 
to total work time accumulated by that population. The 
MSHA mine accident data file can be utilized to obtain the 
number of maintenance accidents that occurred; however, 
because it does not provide a breakdown of worktime data, 
it is impossible to determine maintenance accident inci- 
dence rates. It is possible, though, to estimate the 
maintenance incidence rate. The basis of the estimate is 
the assumption that maintenance worktime was a constant 
percentage of total worktime during the 1978-85 period. 
If this assumption is correct, then the ratio of maintenance 
accidents to total worktime over that period should be indic- 
ative of and proportional to the maintenance accident 
incidence rate: 



= (A) x (200,000)/M, 
= (W) x (K), 

= (A) x (200,000)/(W) x (K), 
x (K) = (A) x (200,000)/W, 

= maintenance accident incidence 

rate, 
= number of maintenance accidents, 
= maintenance worktime, 
= total worktime, 
= the percentage of total worktime 

devoted to maintenance. 



if 


R 


and 


M 




R 


then 


(R) 


where 


R 




A 




M 




W 


and 


K 



By this analysis, the maintenance accident incidence 
rate is shown to be proportional to the ratio of maintenance 
accidents to total worktime. As seen in table 1, the overall 
accident incidence rate from surface metal and nonmetal 
mining showed a steady decline during the 1978-85 period. 
During that same time, the ratio of maintenance accidents 
to total worktime remained relatively constant, suggesting 
that the maintenance accident incidence rate did not decline 
along with the overall accident rate. If, in fact, the ratio 
of maintenance worktime to total worktime declined dur- 
ing that period (as has been suggested because of the 
prevailing economic conditions), it is more probable that the 
maintenance accident incidence rate actually increased. 



Table 1 .—Accident incidence rate in surface metal-nonmetal 
mining 











Maintenance injuries 


Year 


Worktime, 


Injury 


Incidence 




Total work- 




10 3 h 


accidents 


rate 




time, 10 6 h 


1978 


70,784 


2,477 


6.91 


99 


1.40 


1979 


74,912 


2,571 


6.86 


156 


2.08 


1980 


72,404 


2,069 


5.72 


149 


2.06 


1981 


72,516 


1,794 


4.95 


112 


1.54 


1982 


44,612 


968 


4.34 


33 


.74 


1983 


38,144 


760 


3.98 


61 


1.60 


1984 


. . 39,108 


791 


4.05 


55 


1.41 


1985 


35,058 


760 


4.34 


57 


1.63 



ACCIDENT SEVERITY 



The ADA program was used to sort the maintenance 
injuries from the MSHA surface mining accident records 
for 1978 through the third quarter of 1986. Only records 
for which the specified activity at the time of the accident 
was maintenance, and which involved the specified 
machines, were selected. 

Using this criteria, records of 785 injury accidents were 
obtained. Of the accidents, 8 resulted in fatalities, 436 
resulted in lost-time accidents, and 65 resulted in restricted 
time accidents. The total lost time was 11,024 days; of these, 
5,966 days lost were due to accidents involving trucks and 
the remaining 5,058 days to the other three machine classes. 
A total of 71,405 statutory days was charged; 40,245 due 
to trucks and 31,160 due to the other machines. Finally, 
666 days of restricted or limited duty work resulted from 
the injuries, in addition to the lost and statutory days. Of 
these restricted days, 283 were due to truck accidents and 
383 were due to the other machines. 



As might be expected, the personnel involved were 
predominantly mechanics and surface miners. Presumably, 
the surface miners were the operators of the equipment 
although it is not possible to establish this in each case. 
Table 2 presents data regarding injuries and occupations 
of individuals involved in maintenance accidents of all 
machines. The data in table 2 suggest that surface miners 



Table 2.— Severity of maintenance injuries by occupation, all 
machines 



Job 
title 



Accidents 



Severity, 
days lost 1 



Av severity, 
days lost 



Surface miner 
Mechanic- 
electrician . . 
Other 



237 



421 
127 



40,327 

32,709 
9,771 



170 



78 
77 



Total or av 



785 



82,807 



105 



'Includes statutory days charged. 



77 



engaged in maintenance activity have more severe acci- 
dents than do the other groups. 

Table 3 shows the type of accident involved in each 
injury for the combined data of all machines. Both frequency 
and severity of accident types are shown. Similar data are 
presented in tables 4 and 5 for the separate categories of 
trucks and other machines. The appendix provides a more 
detailed description of the various accident types. 



Severity, 
days lost 



Table 4.— Truck injury accident types 

Ac ^ d e ent Frequency 

Caught 72 

Hit-by 122 

Falls 77 

Overexertion .... 51 

Other 69 

Total or av 391 



26,375 

16,744 

1,854 

649 

732 



Av severity, 
days lost 



366 

137 

24 

13 

11 



46,354 



119 



Table 3.— Frequency and severity of accident types for all 
injuries 

Accident Frpnupnrv Severity, Av severity, 
type frequency days lost days lost 

Caught 154 48,525 315 

Hit-by 264 16,396 62 

Electric shock ... 7 9,624 1 ,375 

Falls 150 3,892 26 

Overexertion 98 2,236 23 

Other 112 2,134 19 

Total or av 785 82,807 105 



Table 5.— Other machine accident types 

Accident Fmnupnrv Severity, Av severity, 
type i-requency days lost days lost 

Caught 82 21,596 268 

Electric shock .. . 5 9,576 1,915 

Falls 73 1 ,966 27 

Overexertion 47 1 ,420 30 

Hit-by 142 1,238 9 

Other 45 297 7 

Total or av 394 36,453 93 



TRUCK SYSTEM AND COMPONENT ACCIDENT ANALYSIS 



The previously discussed analysis has demonstrated the 
seriousness of maintenance accident problems in surface 
metal and nonmetal mining. However, before corrective 
action is possible, a greater understanding of the problem 
is necessary . Of particular concern is the determination of 
accident incidence rates corresponding to maintenance of 
specific vehicle subsystems and components. Maintenance 
tasks that have unusually high accident incidence rates can 
then be targeted for special attention (improved job design, 
tools, training, etc.). 

As noted, the MSHA worktime data base is not suitable 
for determining these incidence rates because only industry- 
wide worktime totals are provided. It is impossible to deter- 
mine the amount of worktime devoted to maintenance as 
a whole, much less the time spent on a specific vehicle 
system or component. 

As a first step toward estimating the incidence rates for 
truck subsystems, a detailed breakdown of maintenance 
worktime was obtained from a large surface taconite (iron 
ore) mine. The data cover a 1-yr period, and include the total 
maintenance worktime devoted to each of 18 major sub- 
systems and components for a fleet of end-dump haulage 
trucks. An analysis of this maintenance worktime data, 
together with MSHA maintenance accident data, yielded 
the maintenance accident incidence rates shown in table 6. 

The haulage trucks subsystems were evaluated for acci- 
dent frequency and injury severity. The objective of this 
analysis was to pinpoint subsystems that have a signifi- 
cantly higher degree of associated risk than expected, 
relative to the time spent working on the subsystem. 

In order to evaluate the relative hazardousness of the 
subsystem, a standard statistical assumption was made. It 
was assumed, as a null hypothesis, that accident incidence 
rates would be equal between the various truck subsystems; 
that is, working 10 h on subsystem A would be equally 
hazardous to working 10 h on subsystem B. While practical 
experience suggests that this is not the case, such a null 
hypothesis is the first step in mathematically establishing 



the relative hazardousness of the different subsystems. 
Standard statistical evaluation proceeds by proving or 
disproving the null hypothesis of the systems. The data base 
was analyzed in terms of the proportion of accidents 
resulting from work on each subsystem and for the propor- 
tion of the number of days lost because of injuries resulting 
from work on each subsystem. 

The frequency of accidents and seriousness of injuries 
were expressed as ratios of the observed values to the ex- 
pected values. For example, if the time spent on the 24-V 
electric subsystem represented 5 pet of the total 
maintenance time spent on all subsystems, then the ex- 
pected number of accidents associated with the 24-V sub- 
system, in keeping with the null hypothesis assumption that 
all subsystems are equally hazardous, would be 5 pet of the 
total accidents for all subsystems, resulting in an observed- 
expected frequency ratio of 5/5 or 1.0. If the number of ac- 
cidents associated with that subsystem represented 10 pet 

Table 6.— Truck subsystems, accident frequency and injury 

severity ratios, and excessively high accident rates or injury 

severity 1 

Subsvstem Frequency Severity 

' (observed/expected) (observed/expected) 

Air system 0.7698 0.2805 

Blower 1.1400 .0702 

Box .4438 .6267 

Brakes 1 .5663 1 .6888 

Cooling system 2 4.8380 2 4.8102 

Engine 1.3115 1.7010 

Exhaust 1.0813 .3415 

Frame .8763 .7268 

Fuel system 2.3140 1.4535 

Hydraulic 1.1350 .5714 

Cab 1.0265 .7478 

Steering 1 .4872 2.4402 

Suspension 2 8.4386 2 1 0.4737 

Tires 28.2092 2 6.7449 

Electric brake .2292 .0069 

Electrical power system . 1.0074 .9448 

Radio .4857 Undefined 

Wheel motors .2228 .0184 

'Total number of truck maintenance hours was approximately 13,000. 
Significantly more hazardous than other subsystems. 



78 



of the total accident frequency, then the accident frequency 
ratio for that subsystem would be 10/5, or 2.0, exactly twice 
as many accidents as expected. Similarly, a ratio value less 
than 1 would indicate fewer accidents than expected. Based 
on a comparison of values derived from these ratios with 
standard statistical tables (4), the original null hypothesis 
is proven valid or invalid. 

Ratios of this type were calculated for the frequency and 
severity of injuries incurred in working on each of 18 
haulage truck subsystems. As expected, the assumption of 
equal hazardousness implicit in the null hypothesis was 
disproven, and further analysis of the hazardousness of the 
truck subsystems was performed. 

In order to assess the relative hazard of working on the 
subsystems, a 95-pct-confidence interval was constructed 
for the means of both the severity and frequency ratios. This 
confidence interval is a statistical statement of confidence 
that the average value of a group of values will fall within 
a specified range 95 times out of 100, with repeated sam- 
pling. This range of values takes into account the random 
fluctuation of the average value. As an example, consider 
rolling a die repeatedly. Kit is a fair die, that is, if all faces 
of the die have an equal probability of coming up, the 
average value of the faces that show is 3.5. A 95-pct- 
confidence interval for this average value of a group of rolls 
might be that the average should be no less than 2.5 or no 
greater than 4.5. An average greater than 4.5 would sug- 
gest, with 95 pet probability of being correct, that the high 
numbers, 4, 5, and 6, were coming up more frequently than 
could be explained by change alone. 

The confidence interval for both severity and frequency 
ratios indicated that a mean value of 1.0 would be 
statistically defensible for each. Once this was established, 
it was then possible to identify ratios that were outside the 
confidence interval. Ratios for any subsystem identified as 
being outside the confidence interval (either greater or less 
than the specified range) represent activities that are either 
more or less hazardous than all truck-maintenance jobs con- 
sidered as a group. Ratios that are significantly less than 
1.0 represent activities that are much less hazardous than 
the average; ratios that are significantly greater than 1.0 
indicate more hazardous tasks. 

In the case of the severity ratios, any subsystem with 
a value less than 0.58 may be considered as significantly 
less hazardous than the rest, and values greater than 3.6279 
are significantly more hazardous. Frequency ratios less 
than 0.7478 may be considered as significantly less hazard- 
ous, ratios greater than 3.3170 are considered significantly 
more hazardous. 

Table 6 presents the truck subsystems, accident fre- 
quency and injury severity ratios, and the truck subsystems 
for which accident incidence or injury ratios exceed the 
95-pct-confidence interval. 

As may be seen in table 6, three subsystems are iden- 
tified as outside the confidence intervals for both frequency 
and severity of maintenance accidents, indicating that at 
the 95-pct-confidence level, the high observed frequency 
and/or severity cannot be attributed merely to random scat- 
ter in the data. These subsystems are cooling, suspension, 



and tires. Further analysis of these subsystems was con- 
ducted utilizing the data base compiled from accident nar- 
ratives at the Bureau's Twin Cities Research Center 
(TCRC). Information extracted from the MSHA accident 
narratives that is not readily available in the ADA data 
base, such as specific part worked on, activity of the injured, 
etc., has been included in the TCRC data base. Brief 
characterizations of these accidents follow. 



COOLING SYSTEM 

Accidents involving the cooling system vary in their 
nature, according to the location in which they happen. 
Those that occur inside a shop tend to result from filling 
the system or when removing or installing components, par- 
ticularly the radiator itself. Accidents that occur while fill- 
ing the system result from poor or inadequate workstands. 
A small category of shop accidents involves workers becom- 
ing caught in moving components such as fans and belts. 

It is difficult to ascertain what events are associated 
with removing or installing cooling subsystem components. 
It appears that the components are often inadequately sup- 
ported while being removed or installed, and that access 
constraints require workers to be in unsafe positions when 
considering the inadequate supports of the component. 

Field accidents related to the cooling system 
predominantly involve inspection of the system. It seems 
that workers are removing the radiator caps while the 
coolant is hot and under pressure. A small category of field 
accidents also involves removing or installing subsystem 
components, again predominantly the radiator. The ac- 
cidents also seem to result from the use of inadequate 
workstands. 



SUSPENSION 

Shop accidents involving the suspension system tend 
to occur during removal or installation of subsystem com- 
ponents. The difficulty of gaining access to and supporting 
these components contributes to this type of accidents. A 
second shop activity that results in accidents is servicing 
the suspension system. These accidents seem to result from 
poor workstands and access problems. 

Field accidents involving the suspension system seem 
to result from the difficulty of access to inspect the com- 
ponents. Poor or inadequate workstands were again iden- 
tified as a contributing factor. 



TIRES 

Shop accidents involving tires predominantly involve 
removing or installing the tires. Moving the tires is also 
a major source of accidents. Explosion of the tires during 
servicing is a well-known hazard. 



79 



POTENTIAL METHODS OF DECREASING ACCIDENTS AND INJURIES 



The occurrence of accidents has been described in the 
literature within two different conceptual frameworks. In 
the first model, accidents are described as the direct result 
of unsafe acts or unsafe mechanical or physical conditions. 
Some safety experts believe that as many as 90 pet of all 
accidents are the result of unsafe acts by the workers (5). 
Others believe indirect, or proximal factors to be the cause 
of accidents. These indirect causes include (1) a poorly 
designed workplace, tools, machinery, or other physical con- 
ditions of the environment, (2) an incompatible match be- 
tween the worker and the job, and (3) failure to provide a 
supportive climate for a well-designed and well-executed 
safety program (5). 

Complete acceptance of the first point of view blames 
accidents on the victim. The latter viewpoint lays the blame 
on the equipment. According to one authority (5), "The 
middle-ground realities are, first, that tools, machinery, and 
systems are for the most part not designed to be human fail- 
safe; certain kinds of errors made by humans will lead to 
accidents and injury. The second reality is that unsafe acts 
resulting from human errors, carelessness, or negligence 
do occur frequently in spite of the fact that the average 
employee is an intelligent, careful, and conscientious per- 
son. These unsafe acts and errors occur because of such 
things as lack of knowledge, lack of skill, lack of recent ex- 
perience, inattentiveness, fatigue, and mental-physical 
environmental stressors." 

Some of the factors suggested in this latter analysis as 
causes of accidents could be applied to maintenance safety. 
Previous research conducted by the Bureau under contract 



J0215007 has suggested that unfamiliarity with the job is 
related to the occurence of accidents. Maintenance of a piece 
of modern mining machinery is a complex task. A common 
complaint is that maintenance manuals are difficult to use, 
resulting in a sometimes ineffective manner of training 
maintenance workers (1). It is not surprising that knowledge 
of a safe way to work is as difficult to acquire as is the basic 
knowledge needed to perform the work. A potential way of 
addressing both problems is to revise the maintenance 
manuals, perhaps along the lines of the procedure charts 
used by some mine maintenance operations. These pro- 
cedure charts present information used to perform some 
function, such as changing oil, in a simple, step-by-step list. 
Special hazards, required tools, and recommended safety 
procedures could be included for reference by the workers. 
A second factor noted by Miller (5) is the compatible 
match of the worker with the job. Procedure sheets, similar 
to procedure charts, could be used to identify risk-associated 
actions, such as heavy lifting. For example, a maintenance 
mechanic may be required to lift a fairly heavy object dur- 
ing the course of a repair. Acceptable lifting loads vary 
among workers and also by the frequency with which they 
can be done in the course of a workday (5). Identification 
of such high-risk lifting required by a maintenance job 
might lead to specifications of who could lift, or it might 
require the use of some mechanical system to perform the 
lift. The use of such procedure sheets could enable the rating 
of the physical demand of a job, and high-risk workers could 
be selected out before injuries occur. 



SUMMARY AND RECOMMENDATIONS 



While the incidence of all types of accidents in surface 
metal-nonmetal mining appears to be decreasing, 
maintenance injury accident rates have remained constant 
and represent a high-cost item, with an average of 189 days 
lost per accident. 

Caught, hit-by, falls, overexertion, and electrical shock 
account for most maintenance accidents in both accident 
frequency and injury severity. Maintenance of the cooling 
system, suspension, and tires of haulage trucks are par- 
ticularly hazardous in terms of accident frequency and in- 
jury severity. Further analysis of maintenance of these 
systems suggests that better work platforms, improved 
methods of supporting heavy components, and improved 
methods of moving heavy components would be of benefit 
in reducing maintenance accident frequency and severity. 
A brief description of these acccident types is presented in 
the appendix. 

Training and education of workers to appreciate the 
hazards associated with maintenance work would also 
appear to be of use. Periodic refresher training for 
maintenance workers; the implementation of simple proc- 



ess charts detailing procedures, tools, and potential hazards; 
the use of supports such as slings to support heavy items 
while they are removed or returned to the machine; and 
the use of stands to work on elevated machinery should be 
encouraged. 

Most of these recommendations are based on common 
sense. The question may be posed: Why do people persist 
in working unsafely? A possible answer may lie in the 
psychological effects of the relative frequency with which 
unsafe behavior results in accidents. Not every incidence 
of unsafe work behavior is followed by an accident or in- 
jury. Consequently, the feedback a worker received about 
his or her work methods is mixed or misleading; e.g., "I've 
done it this way a hundred times before, and nothing bad 
has every happened." 

A final recommendation would be to develop and apply 
behavioral controls to supplement the engineering controls 
already in use in the surface metal and nonmetal mining 
industry. Such controls could reduce the confusion in feed- 
back to workers about the safety of their work behavior. 



80 



REFERENCES 



1. Long, D. A. Off Highway Haulage Truck Maintenance Safety. 
Professional Safety, v. 29, 1984, pp. 28-32. 

2. Bowers, E. T. Using ADA (Accident Data Analysis) in Mine 
Safety Research. BuMines OFR 72-86, 1986, 111 pp. 

3. U.S. Mine Safety and Health Administration. Mine Injuries 
and Worktime Quarterly, Closeout Edition 1985. MSHA Div. of 
Mining Inf. Systems (Denver, CO), 1986, p. 3. 

4. Walpole, R. E., and R. H. Myers. Probability and Statistics 
for Engineers and Scientists. McMillan, 3d ed., 1985, 650 pp. 

5. Miller, J. M. The Management of Occupational Safety. Sec. 
in Handbook of Industrial Engineering, ed. by G. Salvendy. Wiley, 
1982, pp. 6.14.1-6.14.18. 

6. Mason, W. A. Metal/Nonmetal Electrical Injuries Involving 
Voltages Over 650 Volts, 1978-1983. MSHA Br. of Injury and 
Employment Inf. (Denver, CO), undated, 4 pp. 



7. Quisenberry, S. Hand and Finger Injuries. MSHA Br. of In- 
jury and Employment Inf. (Denver, CO), undated, 4 pp. 

8. Seals, E. D. Analysis of Bulldozer Injuries at Surface Coal 
Mines, 1979-1981. MSHA Br. of Injury and Employment Inf. 
(Denver, CO), undated, 9 pp. 

9. Chaffin, D. B., and G. Andersson. Occupational Biomechanics. 
Wiley, 1984, 454 pp. 

10. Seals, E. D. Analysis of Shovel and Dragline Accidents. 
MSHA Br. of Injury and Employment Inf. (Denver, CO), undated, 
7 pp. 

11. Marshal, G. Safety Engineering. Brooks Cole Eng. Div., 
(Monterey, CA), 1984, 425 pp. 



81 



APPENDIX.— DESCRIPTION OF SEVERE ACCIDENT TYPES 



ELECTRICAL SHOCK ACCIDENTS 

Electrical shock accidents are the most serious accidents 
in terms of associated severity. In a recent MSHA study 
(6), 1 electrical accidents occurring during maintenance were 
found usually to involve inadvertently brushing the hand 
or arm against a live circuit. Other accidents occurred when 
the individual did not realize that the component being 
worked on was in a circuit, or when power was inadvert- 
ently applied to a circuit that was being worked on. 

Of 12 fatalities cited in the MSHA study, 9 involved per- 
sons who were not qualified to work with electricity. Many 
of these people were engaged in painting, cleaning, or other 
housekeeping duties around high-voltage circuits. 

Recommendations made in this MSHA study include 
shutting circuits off and locking them out when work is to 
be done on or near them, including the replacement of fuses, 
and the installation of panels that provide a barrier between 
the worker and the circuits. 



use of platforms may prevent tools dropped by workers 
above the ground level from striking others who may be 
stationed beneath the worker to warn other individuals to 
keep out of harm's way. 



OVEREXERTION 

A sizable portion of all maintenance accidents and in- 
juries examined in this study resulted from overexertion 
where overexertion refers to lifting or push-pull strains. 
There are current recommendations for such operations that 
can be used for the development of guidelines describing 
when it is safe to lift, when it is safe to push or pull, and 
when it represents an unsafe action (9). 

Analysis of accident records suggest that a very com- 
mon cause of overexertion injury is the removal or installa- 
tion of a heavy part without supporting it in some manner 
(S). 



CAUGHT ACCIDENTS 

Next to electrical shock, caught accidents are the most 
serious of all accidents in terms of their severity. When the 
relative frequency is considered, caught accidents may be 
considered as the most severe of all. Previous research has 
suggested the benefits of securing truck boxes when they 
are raised during maintenance and the use of nylon web- 
bing slings where possible to suspend parts. 

Many amputations have been reported from mechanics 
inserting fingers or hands into boltholes, etc., to check align- 
ment (7). Many caught accidents and injuries result from 
the worker being in the wrong place, that is, being pinned 
between the object being moved and some other component 
of the machine. This can occur when a heavy part is re- 
moved without some support (8). 

Another serious category of caught-type accidents in- 
volves the lubrication, adjustment, or removal of parts while 
the equipment is operating (8). 



HIT-BY ACCIDENTS 

The hit-by category represents a very large portion of 
truck maintenance accidents. Some of these accidents may 
be difficult to anticipate, others are not. For example, the 



'Italic numbers in parentheses refer to items in the list of references 
preceding this appendix. 



FALLS 

Of all the accidents investigated, nearly 21 pet occurred 
while the worker was getting on or off the equipment. A 
common accident of this type results from the workers 
carrying objects in their hands while climbing ladders or 
stairs. If they slip while doing so, they are less able to 
recover by grabbing the handrail. 

Another common hazard related to falls is poor 
housekeeping in the work area. Debris may be difficult to 
eliminate from the work area in the pit, but power cords, 
tools, and other odds and ends represent a hazard on the 
shop floor, as do spills of lubricants and other fluids. 

Accident analysis has shown that machine operators 
often slip and fall from their machines in the course of per- 
forming simple maintenance tasks such as fueling, check- 
ing lubricants, and checking coolant fluids (9), a finding con- 
firmed by the present study. 

Maintenance workers are often required to work at some 
height above the ground. Stable work platforms that ad- 
just to the needed height should be available. The design 
of these platforms should take into account that the per- 
son working on them needs to be protected from slipping 
or falling off of them by siderails, etc. Additionally, the plat- 
forms should protect against parts and tools falling off. Sug- 
gestions for the design of work platforms are available in 
reference 11. Safety lines and harnesses should be employed 
as necessary when it is infeasible to provide platforms. 



82 



DETERMINING EFFECTS OF MANAGEMENT 
PRACTICES ON COAL MINERS' SAFETY 



By Gregory Gaertner, 1 Paul Newman, 2 Shelly Perry, 3 
Gerald P. Fisher, 4 and Kenneth Whitehead 5 



ABSTRACT 



A 3-yr study of 10 mining companies and 62 underground coal mines was under- 
taken by the Bureau of Mines to determine the effects of management practices on coal 
miner safety. Results presented in this paper should be considered tentative in that at 
this time the study is midway through the data collection period. 

Findings to this point underline the importance of top management commitment 
to ensuring a safe, productive mining operation. In the sampled companies, a variety 
of practices were used by management to communicate safety priorities, although most 
companies focus on one or two mechanisms. Several effective management practices 
include safety-productivity incentives, disciplinary policies for unsafe behaviors, and 
concerted efforts to investigate accidents and distribute the results of these investiga- 
tions. Less effective mechanisms include repeater programs and rehabilitation clinics. 
The most effective management practices allow participative implementation, fol- 
lowup, and evaluation. They are also generally forcefully advocated by some well- 
positioned company official, not necessarily in the safety function. 



INTRODUCTION 



As a result of the findings from a study performed by 
a task force of the National Academy of Sciences (NAS) 
(1 ), 6 the emphasis on the role of management in promot- 
ing underground safety has increased. The Bureau of 
Mines funded a 3-yr research effort to focus on specific 
managerial practices that tended to influence safety in 
underground coal mining. Westat, joined by the Bitumi- 
nous Coal Research National Laboratories (BCRNL), and 
the Human Resources Research Organization (HumRRO), 
was selected to assess safety trends and practices across 
the mining industry that might help improve future safety 
policies, programs, and practices. 

This paper traces the literature that relates mining 
safety and coal mine management. It also describes the 
methods employed in locating and collecting data from a 



iSenior study director, Westat, Rockville, MD. 

2 Project manager. 

3 Research analyst. 

4 Senior scientist, Human Resources Research Organization, Alexan- 
dria, VA. 

5 Supervisory engineer, Bituminous Coal Research National Laborator- 
ies, Monroeville, PA. 

6 Italic numbers in parentheses refer to items in the list of references at 
the end of this paper. 



cross section of 10 companies representing 62 mines, using 
a variety of data sources and data collection methodolo- 
gies. Finally, it presents evidence on what specific policies, 
practices, and patterns appear to have measurable impact 
on encouraging safe underground mining. 

The findings reported here should be taken as tenta- 
tive for several reasons. First, this paper was prepared at 
the midpoint of the study's data collection period. As a 
result, analyses of trends over time, which will be avail- 
able at the study's conclusion, (September 1987), are not 
currently possible. Second, some refinement in the exist- 
ing measures will be attempted in the remaining year of 
the study. In sum, these results should be taken as prelim- 
inary and provisional, but nonetheless should be consid- 
ered suggestive of directions for researchers and practi- 
tioners. 

The paper begins with a review of relevant literature 
relating mine management and mine safety, in order to 
develop testable hypotheses for the analysis. It then de- 
scribes the methods and measures, and reports some over- 
all characteristics of the sample of companies. It reports 
the results of preliminary analyses, and presents discus- 
sion and summary outlining future directions for this and 
other research application. 






83 



LITERATURE REVIEW 



The NAS study (1 ) formed the basis for the current 
investigation. Two of its conclusions influenced the direc- 
tion of the present study toward organizational character- 
istics and practices as a determinant of safety. NAS found 
that management's commitment to safety, management- 
labor cooperation in the development and implementation 
of safety programs, and the quality of safety training pro- 
vided were related to safety record. In addition, NAS also 
identified the relationship between higher production and 
lower injury rates. While the NAS study provided initial 
direction toward management practices as an influence on 
safety, it also became apparent that further specification 
was needed of the ways in which these factors influence 
observed differences in incidence rate. 



ASPECTS OF ORGANIZATIONAL 
CLIMATE AND SAFETY 

A number of management structures, interventions, 
and practices have been shown in previous research to be 
associated with low injury rates. These range from tradi- 
tional practices such as training, to more recent and inno- 
vative programs, such as incentive systems and organiza- 
tional development techniques. 

Management Structures and Interventions 

Among the processes found to have a relationship 
with decreased injury rates were decentralized decision- 
making, and flexible and innovative management in try- 
ing new procedures and programs (2 ). Davis (3 ), in a study 
of safety practices among award-winning companies, cites 
the importance of top management support and lower 
level participation to the success of safety programs. The 
necessity of participation of personnel (especially union 
personnel) in safety policy formation was confirmed by 
DeMichiel (4) and Pfeifer (5). The latter study suggested 
that in low-accident mines, management put greater em- 
phasis on safety behavior, more often corrected hazardous 
conditions, and emphasized the maintenance of the com- 
pany's safety record, putting less importance on produc- 
tion competition among sections or shifts. 

While training is the main type of organizational in- 
tervention found in the mine industry, Goodman (6) noted 
that the introduction of other organizational development 
methods has increased in underground coal mining. Two 
major comprehensive organizational development experi- 
ments have been performed in U.S. mines. Goodman (7) 
described a major intervention at the Rushton coal mine in 
Pennsylvania. The focus at the Rushton mine was on im- 
provement of both productivity and quality of working life. 
Labor-management problem-solving groups were devel- 
oped to diagnose problems, and introduce, monitor, and 
modify change. Through reorganization of a work section 
into an autonomous work group, the program produced 
changes in work methods (authority system, decisionmak- 
ing, and communication) and the pay system. Fiedler (8) 
introduced training in leadership and supervisory skills 
and techniques such as team building, problem solving, 
coaching, and supervisory skills. Results of the Rushton 
study indicate that there was an increase in miners' 
knowledge of new mining practices and safety procedures, 
as well as beneficial changes in communication, interac- 



tion, and level of responsibility taken by individuals. The 
Fiedler (8) study cites results including safety improve- 
ment, while productivity was not adversely affected. 

Comparatively little research documents the effects of 
training on safety. What research does exist reviews the 
current state of training and calls for improvement in the 
instructional aspects of training, rather than assessing 
training's long-term utility (9-10). In general, a strong 
relationship between generalized safety training and 
lower injury rate has not been shown, although some util- 
ity has been found for training targeted toward specific 
problems, such as the reduction of causes of certain in- 
juries (11). Again, the commitment of management to 
safety programs was found to be the best predictor of train- 
ing effectiveness. 

Incentive Systems 

Incentive systems, a development in the industry fol- 
lowing the 1978 wage agreement, have been implemented 
on a wide basis (86 pet of mines, according to Sloan (12)). 
Compensation systems are usually composed of a base rate 
and additional bonus for production above a specified 
target. Most plans include safety factors in addition to or 
as limiting conditions on production bonuses, although 
there are financial disincentives for nonproduction activi- 
ties that may affect safety (13 ). Many new incentive plans 
exist, but little systematic evaluation has been done of 
their effects on productivity or on safety. 

The literature review identified only two case studies 
describing the relationship between a production incen- 
tive system and safety. Stanek (14) described the effect 
one company's bonus program has had on safety, a de- 
crease in incidence and violation rates. However, a very 
recent study by Page (15), also seems to point to the use of 
incentives in high-production, safe mines. 

Case Studies of Safety Environments 

In order to provide a portrait of current underground 
mining safety practices, the results of case studies aimed 
at identifying factors related to safety are presented, based 
on Braithwaite's study (16) of the safety environments of 
five companies with the lowest accident rates in the early 
1980's. The following characteristics found to be responsi- 
ble for safe performance were: 

1. Safety practices integrated vertically throughout the 
company. — These include individual-level practices such 
as safety-related job analysis, training by supervisors of 
miners in safe job procedures; weekly contact by supervi- 
sors with miners, for informal training and monitoring of 
safety practices; formal monthly safety observations of 
each employee; and administrative maintenance of em- 
ployee safety records. 

2. Accident investigation. — Investigation was thorough 
and multilevel, and attempted to identify the underlying 
cause of the accident. Investigations pinpointed types of 
violations that caused a number of injuries, or physical 
conditions contributing to accidents and injuries. 

3. Communication. — Sharing of information was pro- 
moted at meetings where accidents were analyzed and 
safety innovations discussed. Peer pressure was also ap- 
plied to managers with poor safety records, through dis- 
cussion of their problems and plans for remediation. 



84 



4. Top management commitment. — Often, safety had a 
higher priority than production or was considered an inte- 
gral part of production. 

Across the board, safety personnel were found to have 
a strong informal leadership position, backed by top man- 
agement commitment to safety. Responsibility was placed 






on the line manager to ensure safety within his or her area 
of accountability. The successful companies combined a 
centralized focus on safety through policy setting with de- 
centralized safety practices through line management re- 
sponsibility for implementation and performance. 



HYPOTHESES 



Based on the results of previous research, the follow- 
ing hypotheses were formulated to guide the investigation 
into companies and mines: 

1. Top management commitment to safety is associated 
with miner safety. — Corporate leadership has been shown 
in a number of areas of research to be a critical factor of 
influence on safety. In the several studies, however, top 
management commitment has been defined in different 
ways. This study will specify critical components of com- 
mitment, its development process, and application to 
safety practices. 

2. Safety strategies effective in the reduction of overall 
injury -accident rates will integrate various management 
control mechanisms to ensure consistency and use. — It was 
contended that a strongly advocated safety policy, com- 
bined with decentralized governance and reinforcement of 
safety practices, is most effective in ensuring low accident 
and injury rates. Simultaneously, the emergence and im- 
plementation of strategies at lower organizational levels 
are likely to interact to produce favorable outcomes. 

3. The existence of a safety incentive system is associated 
with better safety records. — The existence of a company 
incentive program that rewards employees for safe per- 
formance will result in a lower injury rate compared with 



rates of companies with no programs. The mechanisms 
responsible are likely to be the demonstration of top man- 
agement commitment to safety and motivation of em- 
ployees to exert informal control over on-the-job safety 
practices. 

4. Organizational climate factors and labor- 
management relations are influential on safety records. — 
Participative decisionmaking and decentralization of au- 
thority are hypothesized to be influential on safety. 
Previous research has provided support for the benefits of 
participation and delegation, which are thought to foster 
consensual behavior and motivation for safety. Adversar- 
ial labor-management relations are hypothesized to be in- 
versely associated with mine safety. This study will at- 
tempt to clarify whether unsafe conditions create an 
adversarial climate, an adversarial climate causes more 
injuries, or additional factors may be influencing both 
variables. 

5. Safe coal mining operations tend to be productive 
ones. — This hypotheses has received consistent support in 
previous research. What has yet to be specific, however, is 
what management practices are responsible for this rela- 
tionship. 



METHODS 



In-depth case studies were conducted with a sample of 
coal mine operating companies that had volunteered to 
participate in the research. Site visit teams examined nu- 
merous elements of company safety and management pro- 
grams, as well as a combination of statistics reported to 
the Mine Safety and Health Administration (MSHA), 
statistics maintained by the companies themselves, and 
measures of management climate and policy enforcement 
as reported by managers, supervisors, and hourly em- 
ployees. 



COMPANY PARTICIPATION 

Project staff contacted safety directors and other 
known industry contacts at the coal producing companies 
to solicit voluntary participation in the research effort. 
The final sample was composed of 10 coal mine companies, 
operating 62 mines. Variety was achieved in the final sam- 
ple in terms of geographical dispersion, company size, 
ownership patterns, number of mine sites, union- 
nonunion representation, and safety records. 

Mine companies and sites were located in eight differ- 
ent States; Virginia, West Virginia, Pennsylvania, Ohio, 
Illinois, Kentucky, Alabama, and Colorado. 



Participating companies were diverse in size, whether 
measured by market share, number of operating mines, or 
employee population. Two of the ten companies rank 
among the Nation's largest coal producers, while several 
of the companies have only one operating mine. The major- 
ity of participating companies have more than one mine 
and operate in a single State. 

Miners in 7 of the 10 mining companies were repre- 
sented by the UMWA; the other three companies were 
nonunion. 

Overall, the study represents a cross section of compa- 
nies with excellent safety records as well as others across 
a full range, including some with lost-day accident rates 
exceeding the national average. 

Table 1 provides an overview of the 10 companies that 
agreed to participate in the field study. The table provides 
the overall incidence rate for each company, as calculated 
from accident-injury, production, and employment statis- 
tics provided by the Mine Safety and Health Administra- 
tion (MSHA). The rates are calculated across the 5-yr pe- 
riod from 1980 through 1984, and across all mines 
identified as operated by the participating company. 
While the national average for incidence rates based on all 
injuries in underground coal mines was 10.07 in 1983, the 
10 companies average incident rate for 1980 through 1984 



85 



Table 1.— Summary descriptions of participating companies 

(Annual averages of 1 980-84 5-yr period) 



Company 


MSHA incidence 
rate 


Production, 
st 


Employees 


Employee 
hours 


Hours per 
employee 


1 


15.25 


838,246 


277 


548,508 


1,980 


2 


9.94 


328,322 


113 


199,508 


1,763 


3 


2.79 


404,042 


117 


236,606 


2,022 


4 


8.83 


925,345 


474 


888,226 


1,879 


5 


10.32 


561,646 


172 


307,385 


1,787 


6 


12.96 


119,797 


59 


94,505 


1,602 


7 


7.76 


55,081 


28 


28,629 


1,022 


8 


11.97 


279,579 


124 


220,496 


1,778 


9 


4.22 


512,468 


170 


358,671 


2,110 


10 


6.38 


143,568 


18 


36,055 


2,003 


Av . . . . 


9.04 


416,810 


155 


291,828 


1,883 



was 9.04. The 10 companies can, therefore, be considered 
a fair cross section of coal producing companies in terms of 
historical incidence rates. 

Site Visits 

Site visit procedure involved the collection of quanti- 
tative and qualitative data for case study descriptions and 
later analyses. Information was obtained from a number of 
sources while on site, including — 

Interviews with mine and company management repre- 
senting all levels of the organization; 

Mine records (where available) on employment, produc- 
tion, turnover, absenteeism, time off, and disability com- 
pensation; 

Safety department records on accident and injury histo- 
ries, as well as inspection burden and violation history; 

Focus group discussions with supervisors and hourly 
personnel; and 

Responses to semistructured interview questions re- 
garding safety policies and their reinforcement. 

A significant aspect of the present study, which sets it 
apart from other investigations of coal mine safety, is the 
application of organizational models not typically associ- 
ated with the management of coal mining organizations. 
For example, in the first two sections of the site visit out- 
line, the coal company is discussed as an organization (e.g., 
functional departments, organizational structure, and 
lines of responsibility) and in terms of recent corporate 
history (e.g., primary business of controlling interests, 
terms of partnership arrangements, and stockholders' eq- 
uity). 

The semistructured interview format is designed to 
explore both formal and informal company policies and 
training functions, their formation, communication, and 
reinforcement, as well as subjective impressions of and 
reactions to these policies. 

Group interviews, known as focus groups, were con- 
ducted separately with production supervisors and with 
hourly personnel. Focus group sessions permit respond- 
ents to interact freely (and to disagree with one another) 
on specified topics, but maintain the flexibility to discuss 
issues of concern to the respondents. 

Data were obtained from MSHA on all accidents re- 
ported by the selected mines during the 1980-84 period. 
MSHA also provided annual summary statistics for the 
same 5-yr period, for the selected mines' total mine em- 
ployment, total employee hours, total production (in short 
tons), and violations citations. These three data sources 
were matched and merged at the company level. That is, 



accidents and violations data were sorted by company and 
year. Next, counts of each degree of injury, number of 
violations, and number of significant violations (serious 
and substantial (S&S)) were computed for each company 
and year. These company profiles were then matched with 
the company-level production and employment data so 
that incidence, violation, and productivity rates could be 
calculated. (Rates serve to normalize the different mines 
for their employment and production size.) These data are 
presented in table 2. 7 Also reported in table 2 are average 
annual violations and average annual S&S violations per 
mine. 

Table 2. — Status of participating companies on outcome 
variables 1 

(Annual averages of 1 980-84 5-yr period) 



Company 


MSHA incidence 
rate 


Production, 
st/h 


Violations 


Total 


S&S 


1 


15.25 


1.44 


35.16 


16.70 


2 


9.94 


1.65 


30.60 


26.50 


3 


2.79 


1.71 


3.45 


1.25 


4 


8.83 


1.04 


38.80 


13.40 


5 


10.32 


.91 


24.20 


6.27 


6 


12.96 


1.11 


1.60 


.80 


7 


7.76 


1.92 


4.60 


1.20 


8 


11.97 


1.27 


7.80 


4.20 


9 


4.22 


1.01 


21.97 


9.10 


10 


6.38 


3.58 


.97 


.20 


Av 


9.04 


1.56 


16.91 


7.96 



S&S Serious and substantial. 

1 0wing to tempory mine shutdowns and voluntary participation of mines 
within companies, companies cannot be identified by these data. 



Incidence rate statistics computed from the research 
data base were compared with those reported by the com- 
panies themselves during the site visits. These two meas- 
ures agreed to within 10 pet at all but one company. 

Next, comparisons were made of statistics from the 62 
sampled mines with the descriptive statistics reported by 
NAS (1 ). A brief review of these comparisons is provided 
in table 3. In the table, injuries in the seven categories of 
accident types reported by the NAS are cross-tabulated by 
degree of injury. A comparison of the marginal percent- 
ages for the data of this study with results reported by 
NAS reveals a similar distribution of accidents among the 
seven types. That is, the largest proportion of injuries falls 
into the category of materials handling in botb data sets 
(38 pet compared to 34 pet in the NAS report). The next 
largest category, slipping and bumping, also mirrors the 
NAS distribution (26 pet versus 24 pet). In sum, the order 
of proportions among accident type categories is identical 
to those reported by NAS. 

In terms of injury degree, the summary lines at the 
bottom of table 3 display a similar trend in incidence rates 
for each injury degree. This holds true in spite of the differ- 
ent timespans covered by the two data sets (1980-84 versus 
1978-80) and significant differences in sample sizes. These 
findings are characteristic of the kinds of accidents and 
degree of injuries generally observed in coal mining, and 
are therefore expected to remain relatively constant across 
years. 



7 It should be noted that temporary mine shutdowns during the years 
1980 to 1984 and voluntary participation of selected operating mines 
within companies alter these statistics somewhat from MSHA records. 
Individual companies, therefore, cannot be identified from these computed 
rates. 



86 



Table 3. — Distribution of reportable injuries by degree of 
severity and type of accident for 1980-84 



Accident type 


Severity, degree 


Total 


Distribution, pet 


1 


2 


3-5 


This study 


NAS(7) 


Roof-side falls , . 

Haulage 

Machinery 

Electrical-explosive 
Material handling 
Slipping-bumping 
Other 


11 
2 
3 
1 

4 



1 
7 

21 


51 
5 



393 

698 

710 

160 

2,176 

1,530 

49 


405 

707 

734 

161 

2,227 

1,539 

49 


7 
12 
13 

3 
38 
26 

1 


10 
14 
14 

3 
34 
24 

1 


Total 

Injury rates: 

This study 

NAS(f) 


21 

0.04 
0.07 


85 

0.16 
0.17 


5,716 

10.69 
11.80 


5,822 

9.04 
12.00 


100 

NAp 
NAp 


100 

NAp 
NAp 



NAp Not applicable. 

Qualitative Data Coding 

Selected safety policy and company profile informa- 
tion was consensus coded based on the site visit reports. 
The following major topics were included in the content 
coding scheme (coded for presence or absence): 

1. Whether there was a written safety policy. 

2. Whether safety incentives (monetary or awards) 
were offered. 

3. Whether combined safety-productivity incentives 
were offered. 

4. Whether the company had formal investigations of 
lost-time accidents more extensive than those required by 
law. 

5. Whether the company had (and used) disciplinary 
policies applied to safety violations against miners and 
supervisors. 

6. Whether the company distributed information for 
safety meetings. 

7. Whether the company had special programs for min- 
ers suffering repeated accidents. 

8. Whether the company had special programs for in- 
jury rehabilitation. 



Codes were assigned to each company based on details 
in the case study reports, notes from site visit interviews 
and focus groups, and materials provided by the partici- 
pating companies. As shown in table 4, 9 of the 10 partic- 
ipating companies provide formal written safety policies. 
Seven of the companies had some type of safety incentive 
program in place, and three companies had incentives pro- 
grams that rewarded both production and safety. (Produc- 
tion incentives were never found implemented in the ab- 
sence of related safety incentives.) 



Table 4. — Proportion of participating companies reporting 
various elements of safety programs 

Policy element Mean 

Is there a written safety policy 0.90 

Are there incentives for safe operation .70 

Are there incentives for combined safety and production .30 

Are there special accident investigations beyond requirements ... .33 

Are safety discipline policies used .50 

Does company distribute information for safety meetings .78 

Is there a program for accident repeaters .50 

Is there a rehabilitation program .28 



Less common were policies on followup investigation 
programs (beyond the required filing of supervisor's and 
safety director's reports). These were defined as any for- 
mal program, initiated in the aftermath of an accident or 
injury, which was designed to learn more about the cir- 
cumstances of mine accidents and injuries. Three compa- 
nies indicated that specific procedures were in place for 
such a review of each occurrence, including in two cases a 
formal counseling session with each employee involved. 

Employees in six of the participating companies cited 
specific disciplinary actions (e.g., suspensions, penalties in 
job posting, priority in layoff-recall decisions, or dis- 
missals) that would result from identified unsafe work 
practices, such as going out under unsupported top. Five 
operators had established policies to deal specifically with 
repeatedly injured employees, and two had established re- 
habilitation programs and/or clinics for common injuries, 
such as low-back strains. 



ANALYSIS AND RESULTS 



In the analysis to follow, results are presented rele- 
vant to the hypotheses developed. The discussion begins 
by reviewing the interrelations among outcome variables 
to be utilized in the analysis. Results on top management 
commitment, aspects of safety policy relating to safety and 
productivity, and the effects of perceived policy clarity and 
consistency are then reviewed. Data on labor-manage- 
ment relations and the role of safety committees are dis- 
cussed. Finally, evidence on the staffing and organization 
of the safety function is reviewed and summary conclu- 
sions and discussion are presented. 



OVERVIEW OF MINE SAFETY 
AND PRODUCTION OUTCOMES 

Four major outcomes are utilized in the results to 
follow — MSHA incidence rate, tons per employee hour, 
number of MSHA citations per mine, and number of 
MSHA S&S citations per mine. The injury and productiv- 
ity rates were computed by adding the total number of 
reported injuries (or the total number of tons mined) over 
the 1980-84 period for the company, and dividing that 
total by the total number of hours worked for the company 



87 



over the period (times 200,000). The violation and S&S 
counts were the averages of the mines owned by the com- 
pany for the period. 8 

Table 5 presents the intercorrelations among these 
outcomes. Cell entries in table 5 are correlation coeffi- 
cients, using company level rates for the 1980-84 period. 
As should be clear, incidence rates are negatively associ- 
ated with productivity (r = -0.30), and positively associ- 
ated with citations (0.31) and S&S citations (0.31). 



Table 5. — Intercorrelations among safety and productivity 
outcomes 



Correlation coefficient 


1 


2 


3 


4 






MSHA incidence rate 1 


1.00 

-.30 

.31 

.31 


-0.30 
1.00 
-.47 
-.27 


0.31 

-.47 

1.00 

.84 


0.31 


Short tons per employee hour 1 . . . 
Citations per mine 1 


-.27 
.84 


S&S citations per mine 1 


1.00 



S&S Serious and substantial. 
1 Av over 1980-84 5-yr period. 



Productive companies tend to be cited less than unpro- 
ductive ones (r = -0.47 with citations and -0.27 with 
S&S citations), and the two types of citations are closely 
associated (0.84). Thus, in this sample, as with much pre- 
vious literature, productive companies tend to be safe com- 
panies. This finding is particularly important in the dis- 
cussion that follows. 



TOP MANAGEMENT COMMITMENT TO SAFETY 

A variety of previous studies have pointed to the role 
of top management commitment to safety. Perhaps not 
surprisingly, there was very little in the interviews with 
top mine managers that allowed direct discrimination be- 
tween companies where top management was committed 
to safety and where it was not. In fact, it is doubted that 
top management was indifferent to safety in any of the 
sampled companies. Certainly, nowhere was there an atti- 
tude of fatalistic acceptance of high or even moderate in- 
jury rates. 

There were, however, differences in the ways and ex- 
tent to which top management expressed its commitment. 
The first, and most obvious, was in the company's safety 
policy. A second was in the company's choice of vehicles for 
stressing safety. 

Successful companies relied heavily on one or two 
means of promoting safety. In one company, the means 
was training and the use of computerized technology. In a 
second, it was in applying engineering knowledge to pro- 
duction and safety problems. In a third, it was a regular 
formal program of management audits of safety perform- 
ance combined with regularized formal contacts. There did 



8 Pearson's product-moment correlations vary between -1.00 (where pos- 
itive values of one variable are associated with negative values of the other) 
through 0.00 (where the two variables are independent) to +1.00 (positive 
values of one variable are associated with positive values of the other). 



not appear to be one best vehicle for promoting safety, but 
all had several features in common. 

First, the means selected represented a complete se- 
quence of activities in which the workforce could partici- 
pate and which could be implemented, monitored for com- 
pletion, and fed back to management and workforce. 
Followup was a critical part of the safety program. Second, 
the means were promoted by a well-situated advocate, not 
necessarily the company president or safety director, who 
was able to utilize the vehicle to emphasize safety. Third, 
there was frequently considerable pride in the vehicle as 
being invented at and being unique to the company. 

This reliance on safety vehicles is in close accord with 
recent general studies in successful management (17). 
These studies stress the need for a common set of beliefs, 
a structure of action-oriented participative processes, and 
the critical roles of advocates in fostering a climate of 
organizational effectiveness. These points will be further 
refined in subsequent data collection. 

EFFECTS OF SAFETY POLICY 

As noted in the review of the literature, many studies 
have suggested that safety policy plays a key role in mine 
safety. Unfortunately the extant studies, with few excep- 
tions, do not suggest which elements of safety policy were 
important in influencing safety; nor, frequently, do they 
distinguish between policy as stated and policy as per- 
ceived in the mining companies. The studies also were 
generally unable to place the elements of the policy in the 
overall company context. The field methods and data col- 
lected in the current study allow for much more careful 
scrutiny of the relations among elements of policy, reac- 
tions to policy, and effects on safety, productivity, and 
MSHA violation rates. 

Table 6 relates policy elements present in the current 
sample of companies to rates of injury, productivity, and 
MSHA violations. The eight policy elements discussed pre- 
viously were scored as either present or absent at each 
company. 

As noted in the "Methods" section, these scores were 
derived from on-site interviews and document collection. 
The elements were scored as present or absent for each of 
the companies, and these variables form the rows of table 
6. Two types of incentive strategies were coded because 
some companies offered safety incentives or awards alone, 
while other companies used a combination of production 
and safety to reward employees. The most common form 
was to award a bonus on tonnage beyond some norm only 
if no reportable injuries occurred. No companies offered 
production incentives without safety conditions. 

Policy as perceived is measured by the responses of 
supervisors and hourly personnel following the focus 
groups described above. Focus group participants (table 6) 
were asked, on a five-point (strongly agree to strongly 
disagree) scale, to respond to the following statements: 

1. This company's policies on safety are clear to me. 

2. This company's policies on safety are consistent. 

3. This company sometimes pushes productivity at the 
expense of safety. 

4. This company favors automatic temporary roof sup- 
port (ATRS) systems. 



88 



Table 6.— Relationships among policy elements and safety, productivity, and rated policy outcomes 



Policy elements 



Companies 



1980-84 



MSHA 

incidence 

rate 



Production, 
st/h 



Citations 



Per 
mine 



S&S 



Focus group results 1 



Rated policy 



Consistency 



Clarity 



No pressure for 

production over 

safety 



Support 

for 
ATRS 



Is there a written safety policy: 

Yes 

No 

Are there incentives for safe op- 
eration: 

Yes 

No 

Are there incentives for com- 
bined safety and production: 

Yes 

No 

Are there special accident in- 
vestigations beyond require- 
ments: 

Yes 

No 

Are safety discipline policies 
used: 

Yes 

No 

Does company distribute infor- 
mation for safety meetings: 

Yes 

No 

Is there a program for accident 
repeaters: 

Yes 

No 

Is there a rehabilitation program: 

Yes 

No 

Overall mean 



NAp 



9.06 
8.83 



9.04 
9.04 



5.64 
10.50 



6.32 
10.19 



8.20 
9.88 



8.05 
9.38 



10.15 
7.93 

10.13 
8.77 

9.04 



1.62 
1.04 



1.70 
1.26 



2.41 
1.20 



1.33 
1.79 



1.94 
1.19 



1.65 
1.35 



1.49 
1.64 

1.28 
1.64 

1.56 



14.5 
38.8 



16.4 
18.1 



3.0 
22.9 



11.1 
18.6 



16.6 
17.2 



9.2 
34.7 



10.5 
23.3 

27.4 
14.3 

16.9 



7.4 

13.4 



6.2 
13.1 



.6 
8.7 



4.0 
10.8 



7.9 
10.0 



3.4 
9.3 



6.8 
9.9 

14.3 
6.4 

8.0 



1.61 
1.88 



1.47 
1.96 



1.03 
1.94 



1.62 
1.55 



1.24 
1.95 



1.55 
1.94 



1.42 
1.81 

2.04 
1.52 

1.64 



1.88 
2.19 



1.60 
2.53 



1.05 
2.34 



1.62 
1.95 



1.34 
2.37 



1.86 
2.10 



1.81 
1.99 

2.30 
1.80 

1.91 



1.09 
2.31 



1.05 
1.56 



.39 
1.64 



.99 
1.22 



.87 
1.50 



1.14 
1.51 



1.02 
1.38 

1.33 
1.19 

1.22 



1.63 
1.50 



1.51 
1.83 



1.35 
1.75 



1.78 
1.52 



1.39 
1.80 



1.66 
1.47 



1.79 
1.48 

1.51 

1.64 

1.62 



ATRS Automatic temporary roof supports. NAp No applicable. 

1 Low scores indicate greater consistency, clarity, lack of production pressure, and support for ATRS. 



Items 1, 2, and 4 were scored as 1 for strongly agree 
and 5 for strongly disagree. Item 3 was reverse scored, so 
that a high score means that the company is seen as push- 
ing productivity over safety. The items can be interpreted 
in the same way as injury rates — low scores represent 
desirable outcomes. 

Companies with a written safety policy have about 
the same incidence rates as those that do not (incidence 
rates of 9.06 compared with 8.83 respectively). Of course, 
as should be noted, only one company did not have a writ- 
ten safety policy; thus, not much can be said as to the effect 
of the presence of a safety policy in itself. 

Some policy elements, however, are clearly associated 
with safety. Companies with combined safety and produc- 
tion incentives, companies with formal investigation poli- 
cies, and companies with safety discipline policies do tend 
to have lower incidence rates over the 5-yr period than 
companies that do not. 

The association between safety-production incentives 
and safety is particularly striking, especially in light of 
the relative lack of effect of safety incentives alone. Com- 
panies with combined safety and production incentives 
averaged only 5.64 reported injuries per 200,000 h annu- 
ally; companies without combined production-safety in- 
centives averaged an 86 pet higher rate annually. Exami- 
nation of interviews and case study materials clarify the 
difference between safety and production incentives. 
Safety incentives not tied to production tended to be rela- 
tively inexpensive and symbolic (T-shirts, caps, decals), 



and generally did not indicate a serious commitment by 
management to safety in the eyes of the supervisors and 
hourly employees. Rather they were usually intended as 
"reminders to the men, to keep thinking about safety," as 
one manager put it. 

Combined production-safety incentives seem far more 
effective, and generally more costly. In one compnay, the 
cost of the production-safety incentives was 25 cents per 
ton; in another it was 81 cents per ton. Nonetheless, the 
incentives appeared to be effective. As one supervisor put 
it, the incentive program in place in his company "made 
management put their money where their mouth was." 
Certainly, there are strong effects of safety-production in- 
centives on perceptions of policy clarity and consistency, 
indicated in the last four columns of table 6. 

Companies with safety-production incentive pro- 
grams are more likely to be seen as having clear and con- 
sistent safety policies. They are much less likely than 
other companies to be seen as pushing production at the 
expense of safety. These findings are in close accord with 
Page (15); however, several caveats should be noted. 

First, the design of some incentive systems makes 
them less effective. For example, in one company where 
incentives are based on no lost-time accidents for a month, 
the first accident tends to be followed by several others as 
the incentive is no longer in effect. Second, the design of 
the incentive system cannot be divorced from an overall 
management strategy supportive of safety. Third, there is 
reason for concern that incentives seem so effective that 



89 



many observers are concerned that the incentives simply 
encourage miners not to report actual injuries. In one com- 
pany that has strict safety-only award program, managers 
were reluctant to implement a combined safety-production 
incentive for fear of making miners work injured to avoid 
reporting injury and losing their incentive pay. 

There is some empirical support for this concern to be 
drawn from this study. For example, if it is assumed that 
the main effect of incentives is to suppress the reporting of 
minor injuries rather than to increase safety conscious- 
ness, then the difference between companies with and 
without safety-production incentives should be less when 
more serious injuries are considered, because these cannot 
easily be ignored. This is in fact the case. The difference in 
reported injuries between companies with and without in- 
centives was 4.86 per 200,000 employee hours in the aver- 
age year. However, the difference in rates for days-lost 
injuries is smaller — the average rate of days-lost injuries 
over the period for companies with incentive programs 
was 7.17 per 200,000 employee hours; for companies with- 
out them it was 9.70, a difference of 2.53. Thus, there may 
be some tendency for safety-production incentive pro- 
grams to both encourage safe work and discourage injury 
reporting. 

The associations between safety disciplinary policies 
and formal investigations (and to some extent, the provi- 
sion of materials for safety meetings) on the one hand, and 
safety on the other, are less easily explained, and nearly as 
strong. 

About half of the companies visited had stong safety 
discipline policies. There was a strong association with 
whether the company was organized — unionized compa- 
nies were less likely to have safety discipline policies. 
However, several unionized companies had special safety 
discipline policies developed in collaboration with the 
UMWA. When present, such policies seem to have an ef- 
fect on safety (the difference in incidence rates between 
companies with and without special discipline policies was 
1.66 per 200,000 hours annually). 

The importance of the disciplinary policy seemed to be 
less punitive than indicative of top managerial commit- 
ment to safe operations. In one company, for example, it 
was the policy to send home both a miner and his or her 
supervisor if the miner went out under unsupported roof. 
One member of the research team, while underground and 
out of earshot of safety personnel, asked a miner whether 
the policy was serious. He replied, "I got sent home last 
week, and my face boss did, too." When asked what effect 
this had, the miner said, with obvious understatement, 
"We're both a lot more careful about going out under un- 
pinned top now." Certainly where special disciplinary poli- 
cies are present, focus group results suggest that safety 
policy is more likely to be seen as clear and consistent. The 
results for investigations and information distribution are 
similar. 



The common thread of safety-production incentives, 
discipline programs, and special investigation procedures 
is that in each, special attention by management is di- 
rected to problems of safety. This attention was sometimes 
popular (incentives), sometimes not (discipline), but in 
each case showed special focused attention to safety. It 
may be that this top management attention is as impor- 
tant to safety as the specific policy element by which it is 
expressed. 

Two policy elements stood out as not effectively reduc- 
ing reported accidents — repeater programs and rehabili- 
tation clinics. Companies that had special programs to 
deal with repeaters and special programs to supervise or 
speed rehabilitation from injuries had higher injury rates 
than companies without the special programs. 

Two explanations come to mind. First, it may be that 
companies with severe injury problems were driven to 
undertaking repeater and rehabilitation programs. Man- 
agers at companies supporting such programs frequently 
cited the costs of compensation and extended convales- 
cence as reasons for the programs. Alternatively, it may be 
that at companies where repeater and rehabilitation pro- 
grams are supported, there is a tendency for safety to be- 
come part of an adversarial atmosphere between manage- 
ment and the workforce. 

The focus group results suggest that workers in com- 
panies where rehabilitation programs are undertaken 
tend to feel that the company's safety policy is less consis- 
tent and less clear than in companies where such pro- 
grams are absent. Interviews conducted with supervisors 
and hourly personnel during site visits suggest that min- 
ers frequently were distrustful of such programs. The in- 
terview results for repeater programs are less clear cut. 
There was often support in the workforce for counseling 
and weeding out miners who were repeatedly injured, and 
repeater programs were found in companies where labor- 
management relations were quite good. 

Findings of major importance to this study and to coal 
mine safety overall are contained in the MSHA incidence 
rate column of table 6. By way of summary, policies associ- 
ated with company-level safety are also closely associated 
with company productivity. Safety-production incentives 
and discipline policies, in particular, tend to be found in 
companies that are both safe and productive. 

The association between safety and productivity is 
demonstrated even more clearly in the data in table 7. 
This table presents correlations among the focus group 
ratings of policy clarity, consistency, company pressure for 
production over safety, support for ATRS, and among in- 
jury rates, productivity rates, and counts of citations and 
S&S citations. Again, the results suggest that in compa- 
nies where safety policies are seen as clear and consistent, 
where production pressure is not seen to come at the ex- 
pense of safety, and where ATRS is seen as supported, 
reported injuries are lower and production is markedly 



Table 7. — Correlations among rated policies and safety-productivity outcomes, 1980-84 



Mean responses 1 to — 


MSHA incidence 
rate 


Production, 
st/h 


Citations 


Per mine 


S&S 


Company's safety policy is clear to me 

Company's safety policy is consistent 


20.48 

2.63 

.42 

.40 


2-0.75 
2 -.67 
2-.75 
2-.76 


20.70 
.32 
.51 

-.09 


20.59 
.20 


This company sometimes pushes production over safety 

This company supports automated temporary roof supports 


.14 

-.13 



1 1st, 2d, and 4th scored from strongly agree to (1) to strongly disagree (5); 3d reverse scored for ease of interpretation. 
2Statistically significant; p <0.10. 



90 



higher. In fact, the associations between reactions to pol- 
icy and productivity are even stronger than the associa- 
tions between policy reactions and safety. 

The main safety policy elements (table 6) that are 
associated with safety and productivity are also associated 
with low rates of violations and with low rates of signifi- 
cant and substantial violations. Safety-production incen- 
tives, information distribution, and safety investigations 
are all associated with low rates of citation, and low rates 
of S&S citation. As should be clear, the results are the 
same (table 7) for rated policy from the focus groups. 

Other Elements of Policy 

For several other elements of policy, only anecdotal 
information can be provided at this point. 

Training, for example, seems to have to be pervasive 
but have little systematic impact. Only one company of- 
fered training in addition to that required by law. That 
company does have very low accident rates and high pro- 
ductivity, but because that company is remarkable in sev- 
eral respects, it is difficult to attribute its safety and pro- 
duction performance to training alone. It is, however, 
noteworthy that the company's managers do heavily em- 
phasize the role of training in their overall safety strategy. 

Based on the comments received in focus groups, tbe 
quality and relevance of training varies widely among the 
sampled companies. In response to cost pressures, many 
companies have cut back severely on in-house training 
staff, in preference to contractor-supplied training. Three 
companies have the bulk of their training supplied and 
delivered by local university staff. There are no apparent 
safety effects of these trends, but in general these cutbacks 
are recent. The safety and productivity performance of 
companies experiencing training cutbacks will be tracked 
in the final year of the study, for inclusion in the final 
report. 

A second element about which only anecdotal evi- 
dence can be presented is the role of safety meetings and 
contacts. All companies had, as part of their policy, weekly 
safety meetings or huddles on the section, ranging in dura- 
tion from 5 to 30 min. Thus, there is no clear-cut variabil- 
ity in this element. Further, only one company had a reg- 
ularized program of safety contacts, so that there is little 
systematic variability in this element. 

There was wide variety in the utility and relevance of 
the safety meetings, based on the reports of the focus 
groups. In subsequent analyses, the comments on safety 
meetings will be coded to provide more specific feedback to 
industry. Preliminary evidence suggests that the quality 
of safety meetings varies with the amount of specifically 
relevant material supplied by the company to the section 
supervisors and with the extent to which supervisors take 
the meetings seriously. This latter is probably related to 
the overall approach to safety in the company. 

Multivariate Models of Safety Policy Elements 

The preceding discussion distinguished between pol- 
icy as stated in interviews with mine management and in 
documents and policy as perceived in focus group inter- 
views with mine supervisors and hourly employees. One 
reasonable question is, which of these two is more impor- 
tant in producing safety and productivity results? On one 
hand, it is reasonable to argue that policy as stated is the 
ultimate arbiter of managerial action — if the policy exists, 



it is the touchstone for what is allowed, what is not, and 
what is ambiguous. Interviews with managers matter-of- 
factly convey this impression. When asked how the com- 
pany deals with accident investigations or with incentives, 
managers typically referred to the company's policy. On 
the other hand, academics and practitioners are more 
likely to attend to policy as perceived as a reliable guide to 
understanding and prediction. This is especially true in 
safety management, where so much depends on the volun- 
tary compliance of supervisors and hourly personnel, it 
might be argued that policy as stated is irrelevant unless 
it is understood and acted upon by those to whom it is 
intended to apply. 

The data allow at least an illustrative test of these 
alternative arguments, in that data were collected on both 
policy as stated and policy as perceived so that comparison 
of their effects on safety and production outcomes is possi- 
ble. The results of this illustrative test are presented in 
table 8. 



Table 8.— Comparing effects of stated and rated policy on 
safety and productivity 1 





Production-safety 
incentives 


Overall 


Difference 




Yes2 


No3 




MSHA incidence rate: 

Without accounting for rated 
consistency 4 

After accounting for rated con- 
sistency 

Short tons per employee hour: 

Without accounting for rated 
consistency 4 

After accounting for rated con- 
sistency 


5.64 
7.22 

2.41 
2.22 


9.79 
8.91 

1.17 
1.26 


8.35 
8.35 

1.58 
1.58 


4.06 
1.69 

1.24 
.96 



1 Results differ slightly from table 1 because focus group results were not 
available for 1 company. 
2 3 mines. 
3 6 mines. 
4 Difference in means significant; p <0.10. 



Table 8 presents results for MSHA incidence rates 
and results for productivity. The means of companies with 
and without safety-production incentive plans are pre- 
sented, ignoring safety policy consistency ratings taken 
from the focus group. 9 Effects of rated consistency of safety 
policy were removed statistically, 10 and adjusted means 
and differences in them are presented. In nontechnical 
terms, table 8 presents the mean incidence and productiv- 
ity rates companies with and without safety programs 
would be expected to have if these focus groups had safety 
policies rated as equally consistent. 

The results suggest that perceived consistency in 
safety policy is probably more important than the mere 
presence of safety-production incentives in fostering low 
incidence rates. When rated consistency is ignored, the 
difference in incidence rates attributed to safety- 
production incentives is a statistically significant 4.06. 
When rated consistency is statistically controlled, the dif- 
ference attributed to safety-production incentives drops to 
an insignificant 1.69. However, for productivity, effect of 



91116 results differ from those presented in table 6 because for one of the 
companies focus group results were not available. 

10 Technically, this is accomplished by entering rated consistency as a 
covariate and removing its effects on the dependent variable (incidence 
rate or productivity) before recomputing the difference in means. 



91 



policy as stated is probably stronger than consistency in 
safety policy. The difference drops from 1.24 to 0.96. This 
is perhaps understandable in that the variable controlled 
relates directly to safety policy consistency, rather than 
consistency of productivity policy. Nonetheless, even the 
latter result suggests that part of the productivity effect of 
safety-production incentives is obtained by convincing 
workers that the policy occurs in a climate of consistent 
support for safety. 

A second illustrative result from the study can pro- 
vide some insight in understanding the relationship be- 
tween productivity and safety at the company level. The 
preceding discussion noted that productive companies in 
the sample tended to have low incidence rates as well — 
this finding is in accord with NAS {!). It was further noted 
that policies and perceptions of policy that support safety 
also support production. It is instructive to ask, and at- 
tempt to answer, the question, what is it (if anything) 
about companies that explains the association between 
safety and productivity? More specifically, is it possible 
that there is something about organizational climate that 
causes companies to mine both productively and safely? 

The correlation between average annual incidence 
rate and productivity for the sampled companies over the 
1980-84 period is -0.32; that is, companies with high inci- 
dence rates tend to have low productivity. Safe companies 
also tend to be percieved as having comparatively consis- 
tent safety policies (correlation is 0.63) and productive 
companies tend to be perceived as having comparatively 
consistent safety policies (correlation is 0.67). 

Using a statistical procedure similar to that employed 
in comparing the effects of stated and rated policy, the 
rated consistency of safety policy can be controlled statisti- 
cally in assessing the correlation between incidence rate 
and productivity. The results suggest that net of rated 
consistency, the association between incidence rate and 
productivity becomes positive (0.22); that is, in comparing 
two companies with equal rated consistency in safety pol- 
icy, the more productive one will likely be less safe. 

These tentative results are interpreted as follows. At 
the margin, there may be some tradeoff between safety 
and productivity. However, the sorts of companies that are 
productive seem to foster a safety awareness that pro- 
motes both safety and productivity, which far outweighs 
the marginal tradeoff. Safe companies seem to be produc- 
tive companies in part because their managements offer 
policies that convince supervisors and hourly personnel of 
a consistent posture stressing both productivity and 
safety. 

Other additional elements, less of a policy nature, also 
contribute to this awareness and are discussed in the fol- 
lowing sections. 

ORGANIZATION CLIMATE AND LABOR 
MANAGEMENT RELATIONS 

Among the variables studied were the relationships 
among organizational climate, labor-management rela- 
tions, and safety. In general, it was found that the more 
positive the climate and the higher the quality of labor 
relations, the better the safety record. The following types 
of indicators were found in a setting where the climate 
(both labor relations and overall organizational climate) 
was positive: 

An available and often used open-door policy to upper 
management (hourly interviewees said that they spoke 



directly with the chief executive officer or superintendent 
and that they got a perceived positive response); 

A fair percentage of time spent underground by com- 
pany management (hourly employees appreciated under- 
ground contact with upper level management, and infor- 
mal conversation let others know that visits had been 
made); 

A positive feeling and pride on the part of employees and 
supervisors in working for the company (focus group par- 
ticipants indicated that they were proud working with the 
company, and frequently compared notes with family 
members, neighbors and/or friends who worked for other 
companies; safety practices being an early topic of conver- 
sation); 

Multiple communication vehicles were in existence in 
companies with a positive climate (newsletters, numerous 
communications on bulletin boards in the bath-house, let- 
ters sent to the home, Christmas parties for families and 
management, informal meetings with individuals and 
groups of miners). 

Several labor-relations variables were reviewed 
through quantitative-qualitative methods. The first vari- 
able was the current status of the company and its mines 
in terms of unionization. Unfortunately, there were few 
nonunion companies able to participate, so that the direct 
differences between union and nonunion companies could 
not be examined with any confidence. The second variable 
was the perceived labor-relations climate as reported by 
both management, supervisors, and hourly labor. The 
third was the role and activity of the safety committee in 
unionized mines or its equivalent in nonunion settings. 



Perceived Labor-Relations Climate 

In many of the companies visited, the mines had been 
shut down for a year or more during the early 1980's. Once 
they were reopened, only some of the workers were re- 
hired. In many of the companies, less workers were ex- 
pected to produce more tonnage than before the layoffs. 
While technology was often improved, this production goal 
was not always easy to achieve. Management and long- 
term contract holders let the workers know that the price 
of equal or less productivity was shutdown. Miners are 
commonly the highest paid employees in the regions in 
which they live. When asked about the effects of this inse- 
cure atmosphere, one miner stated: "I'm one of five broth- 
ers in my family, and I'm the only one with a job. How am 
I supposed to feel?" Not all of the companies visited were 
in this fragile a condition; yet this situation was far from 
atypical. 

How this situation affected the labor-management re- 
lations climate depended, in part, on how management 
presented the situation to the workforce. In one company, 
several managers independently noted that "each ton we 
dig out of the ground is one ton closer to when we close the 
mine." Not surprisingly, this mine was comparatively un- 
safe and unproductive. In other companies, the approach 
was very different, emphasizing not so much that "to stay 
open we've got to be productive", but rather "we're open 
because we're productive." 

Based on the criteria noted, the labor-management 
relations climate was coded with considerable consistency 
among methods. One method was to code the focus groups 
for positive and negative labor-relations comments. A sec- 
ond was to code the interviews with managers. Interrater 



92 



reliability was 0.71. Table 9 presents safety and productiv- 
ity measures separately for companies with a positive cli- 
mate and with a negative labor-management relations 
(LMR) climate, as taken from the interviews. 

Table 9. — LMR and safety committee effects on safety and 
productivity 





Companies 


MSHA 

incidence 

rate 


Production, 
st/h 


Citations 




Per 
mine 


S&S 


LMR: 

Positive 

Negative 

LMR positive: 

Active 

Passive 

LMR negative: 

Active 

Passive 

Company future: 

Positive 

Negative 


4 
5 

1 
3 

1 
3 

1 



6.70 
11.50 

2.79 
7.98 

10.70 
9.94 

8.83 
9.25 


1.48 
1.23 

1.70 
1.40 

1.02 
1.65 

1.98 
1.14 


9.46 
26.07 

3.45 
11.45 

21.53 
30.60 

10.39 
23.43 


3.94 
12.73 

1.25 
4.83 

6.80 
26.50 

4.70 
11.23 



In accord with previous studies in the area, it was 
found that positive LMR climate is associated with lower 
incidence rates, slightly higher productivity, and lower 
citation and S&S citation rates. In fact, these results are 
nearly as strong as those relating to safety policy. Obvi- 
ously, these two sets of independent variables are corre- 
lated — companies with a positive LMR climate tend to be 
rated as having consistent safety polices. 

Safety Committee 

In each of the mines, there was either a safety commit- 
tee or (in nonunionized settings) a group of hourly em- 
ployees who conducted safety inspections and/or audits. 
The safety committee commonly reflected the general 
labor-relations climate of the company. Where the union- 
management climate was strained, the committee was 
commonly more adversarial than in those companies 
where the relations were placid or highly supportive. 

Overall, two types of committees could be discerned. 
One type was comparatively active. It was common to find 
an active safety committee meeting monthly with the 
safety director, the mine manager and the labor-relations 
director. It was also common to find a safety committee 
member accompanying an MSHA or State inspector dur- 
ing mine visits (along with a company staff member). 
These active safety committees tended to be consulted and 
tended to seek consultation on matters relating to mainte- 
nance, changes in mine ventilation plans, and on safety 
equipment. A second type of committee was more passive. 
Its meetings with management were more infrequent and 
reactive, and its members would only irregularly accom- 
pany MSHA inspectors. Consultation on change was more 
rare. 

Two types of committees were found in both coopera- 
tive and adversarial climates. Their interactions with 
management, by and large, reflected climates — adversar- 
ial in negative climates, cooperative and problem-solving 
in positive climates. 

Table 9 displays the effects of the safety committee on 
safety and productivity outcomes, in such a way as to high- 
light features of interest. In results not shown, it was ap- 
parent that the mere level of activity of the safety commit- 
tee was not consistently related to safety or productivity. 



Rather, the effects of safety committee activity depend on 
the overall LMR climate. While the sample sizes make 
generalization hazardous, the results are suggestive. Even 
where the LMR climate is positive, if the safety committee 
is passive, little difference from a negative LMR climate is 
observed in terms of incidence rate (7.98 average annual 
rate as compared with 10.7 or 9.94). However, a positive 
climate in conjunction with an active safety committee 
shows strong effects on safety (average annual incidence 
rate of 2.79). What is observed is a synergistic effect of 
participation and supportiveness, similar to that found by 
Sanders (2). 

The results for productivity are even more striking. 
Where the LMR climate is positive, an active safety com- 
mittee is associated with higher production; where the 
climate is negative, an active safety committee is associ- 
ated with lower production. 

The effects of safety committee activity and LMR cli- 
mate on citation rate and S&S citation rate are more 
straightforward. Where LMR climate is positive, fewer 
citations are found; where the safety committee is active, 
again fewer citations are observed. It is suspected that 
where a positive LMR climate and an active committee are 
present, conditions contributing to citation rate are not 
allowed to develop, and hazards are dealt with as they are 
discovered. 

A final item on organizational climate bears mention, 
and is shown in table 9. On the basis of interviews and 
focus groups, it was possible to assess prevalent opinion 
within the company on the company's financial future. 
Coded separately from focus groups and interviews, a high 
degree of unanimity was achieved. As the results suggest, 
when the company's future is seen as positive, productiv- 
ity and safety results are positive as well. Whether these 
results reflect a cause-and-effect relationship will be ex- 
amined in the final year of this study. 

SAFETY DEPARTMENT ORGANIZATION 
AND STAFFING 

Several previous studies have commented on the role 
of the safety department in supporting a climate of mine 
safety. Unfortunately, as with several previous elements, 
the role of the safety department is pervasive but not par- 
ticularly systematic. All of the companies in the sample 
had safety personnel at mine and company levels. How- 
ever, many of the companies had experienced cutbacks, 
especially in training personnel. These cutbacks had two 
implications. First, where training and safety personnel 
were in the same department, it was unclear whether 
safety personnel were affected. Second, even where train- 
ing and safety were organized separately, safety personnel 
were increasingly taking on responsibilities, such as es- 
corting MSHA inspectors, which had previously been han- 
dled by training personnel. Thus, attention to accident 
investigations, to special training, and to safety implica- 
tions of equipment and maintenance may have suffered. 

In terms of personnel, the educational qualifications 
of safety personnel seemed less important than under- 
ground experience in creating credibility with the work- 
force. There is, moreover, impressionistic evidence that 
the informal prestige of the safety personnel was higher in 
relatively safe, productive mines, although this was, sur- 
prisingly, not uniformly the case. In companies where the 
safety department had relatively low prestige, however, 
there tended to be another well-placed advocate for safety 
in top management. 



93 



SUMMARY AND CONCLUSIONS 



This paper attempts to identify management practices 
in underground coal mining that can be linked to safety 
and productivity outcomes, based on a study of 10 mining 
companies and their operations. The results should be con- 
sidered tentative and provisional, since the study was mid- 
way through its data collection period at the time this 
paper was prepared. Nonetheless, the findings are sugges- 
tive of future directions for researchers and practitioners 
alike. 

Companies that were successful at mining coal safely 
tended also to mine at high rates of productivity. To ac- 
complish these results, mine managers used a variety of 
techniques, some of them unique to the company, some of 
them uniform across companies. Successful companies fre- 
quently had one or two vehicles they utilized to press home 
safety. While the specific vehicles varied by company, they 
shared the characteristics of (1) identifying complete se- 
quences of activities that were broadly participative, and 
which could be implemented, monitored, and followed up; 
(2) being advocated forcefully by a well-positioned com- 
pany official; and (3) frequently being seen as unique to 
and invented by the company. 

Characteristics of completeness and advocacy (charac- 
teristics 1 and 2) were also true of the specific policy ele- 
ments that were identified as being effective at supporting 
safety and productivity. These included safety- 
productivity incentives, accident discipline policies, infor- 
mation distribution, and formal investigations following 
accidents. There was some evidence that the effects of 
safety-production incentives were to both improve safety 
and to suppress the reporting of minor injuries — the latter 
tendency should, obviously, be monitored with care. There 
were two other programs that should be implemented with 
care — rehabilitation programs and repeater programs. 
These tended to be viewed with much suspicion by the 
workforce and tended to detract from a consistent, clear 
safety policy. 

There was evidence that the major safety effects of 
these policies were accomplished by convincing the mine 



workforce that management was clearly and consistently 
supportive of safety. Absent this awareness, the positive 
effects of management policy, while still present, were 
much reduced. In fact, tentative evidence was presented 
suggesting that the common feature explaining the ten- 
dency for safe companies to be productive ones was the 
capacity of management to convince the workforce of a 
consistent clear posture supporting safe but high produc- 
tion. Labor-management relations and organizational cli- 
mate contributed to this understanding. Where LMR was 
positive, production and safety were higher. Safety com- 
mittees tended to focus on both the positive and negative 
aspects of the LMR climate. Where the climate was posi- 
tive and the committee active, safety and production re- 
sults were positive; where the LMR climate was negative 
and the safety committee was active, production and, to 
some extent, safety suffered. Finally, both safety and pro- 
duction suffered when the company's future was uncertain 
or bleak. 

Results on the staffing and organization of the safety 
department require further analysis. In the current eco- 
nomic climate, there have been substantial cutbacks in 
the training function in particular, with increasing re- 
liance on contractor-provided training. There is no evi- 
dence of negative safety results, but this topic will be mon- 
itored carefully. 

This paper can be seen as placing an unfair burden on 
mine managers. Already strapped by an uncertain market 
for coal, mine managers are responsible both for seeing to 
the financial future of their companies and their safety 
results as well. In fact, however, the findings make clear 
that safety is a shared responsibility, and that when this 
responsibility is shared and reinforced, it benefits not only 
safety, but also productivity. Management is responsible 
for setting and reinforcing safety policies, but these poli- 
cies can only be successfully carried out when there is 
widespread agreement on the importance of safe produc- 
tive operation, and a shared commitment to achieve it. 



94 



REFERENCES 



1. National Academy of Sciences, Committee on Underground 
Coal Mine Safety. Toward Safer Underground Coal Mines. NAS, 

1982, 190 pp. 

2. Sanders, M. S., T. V. Patterson, and J. M. Peay. The Effect 
of Organizational Climate and Policy on Coal Mine Safety. Naval 
Weapons Support Center, Appl. Sci. Dep., 1976, 165 pp. 

3. Davis, R. T., and R. W. Stahl. Safety Organization and Activ- 
ities of Award- Winning Companies in the Coal-Mining Industry. 
BuMines IC 8224, 1964, 26 pp. 

4. DeMichiel, J. M., J. F. Langton, K. A. Bullock, and T. C. 
Wiles. Factors Associated With Disabling Injuries in Under- 
ground Coal Mines. MSHA, June 1982, pp. 1-72. 

5. Pfeifer, C. M. Jr., J. L. Stefanski, and C. B. Grether. Psycho- 
logical, Behavioral, and Organizational Factors Affecting 
Coal Miner Safety and Health. U.S. Dep. HEW, 1976, 319 pp.; 
NTIS PB-275 599. 

6. Goodman, P. S., and R. S. Atkin. The Feasibility of Applying 
Employee Assistance Programs in the Mining Industry. Paper in 
Ergonomics-Human Factors in Mining. Proceedings: Bureau of 
Mines Technology Transfer Seminars, Pittsburgh, Pa., December 
3, 1981, St. Louis, Mo., December 10, 1981, and Denver, Colo., 
December 15, 1981 (comp. by Staff, Pittsburgh Research Center). 
BuMines IC 8866, 1981, pp. 116-131. 

7. Goodman, P. S. Assessing Organizational Change: The 
Rushton Quality or Work Experiment. Wiley, 1982, 391 pp. 

8. Fiedler, F. E., C. H. Bell, Jr., M. M. Chemers, and D. Patrick. 
The Effectiveness of Organization and Management Training on 
Safety and Productivity in Metal/Non-metal Underground Min- 
ing (contract J0387230, Perceptronics). BuMines OFR 191-84, 

1983, 296 pp.; NTIS PB 85-163285. 



9. Atkins, J. 1970-80: A Decade of Progress in Mine Health and 
Safety Training. Paper in Mine Safety Education and Training 
Seminar. Proceedings: Bureau of Mines Technology Transfer 
Seminars, Pittsburgh, Pa., Dec. 9, 1980, Springfield, 111. Dec. 12, 
1980, and Reno, Nev., Dec. 16, 1980 (comp. by Staff, Pittsburgh 
Research Center). BuMines IC 8858, 1981, pp. 16-23. 

10. Digman, R. M., and J. T. Grasso. An Observational Study 
of Classroom Health and Safety Training in Coal Mining (con- 
tract J0188069, WV Univ.). BuMines OFR 99-83, 1982, 65 pp.; 
NTIS PB 83-210518. 

11. Adkins, J., R. Akeley, P. Chase, L. Marrus, W. Prince, R. 
Redick, C. Rogne, J. Saalberg, and L. Szemprach. Review and 
Evaluation of Current Training Programs Found in Various Min- 
ing Environments; Volume II, Analysis and Recommendations 
(contract S0144010, Bendix). BuMines OFR 110(2)-76, 1976, 149 
pp.; NTIS PB 258 043. 

12. Sloan, D. A. Mine Management. Chapman & Hall (New 
York) 1983, 495 pp. 

13. Trist, C, and P. Bamforth. Some Social and Psychological 
Consequences of the Longwall Method of Coal Getting. Human 
Relations, Jan. 1951, pp. 3-38. 

14. Stanek, P. F. Introduction of a Coal Miner Incentive Pro- 
gram. Paper presented at the 1979 Coal Convention of the Amer- 
ican Mining Congress, St. Louis, MO, May 20-33, 1979; available 
from G. Gaertner, Westat, Rockville, MD. 

15. Page, S. J., J. Volkwein, and F. Kissell. Some Continuous 
Sections Can Cut More Than 1,000 Tons Per Unit. Coal Age, Jan. 
1987, pp. 51-55. 

16. Braithwaite, J. To Punish or Persuade. State University of 
New York Press (Albany), 1985, 242 pp. 

17. Peters, T., and R. A. Waterman. In Search of Excellence, 
Wiley, 1982, 242 pp. 



95 



MINER ABSENTEEISM: 
CONSEQUENCES, CAUSES, AND CONTROL 



By Robert H. Peters 1 



ABSTRACT 

This paper presents a summary of in-house and contract research the Bureau of 
Mines has sponsored to determine the consequences, causes, and control of coal miner 
absenteeism. Several significant problems, especially safety, associated with absen- 
teeism among underground coal miners are described, and a conceptual model of the 
factors that cause absenteeism among miners is presented. The highlights of two 
empirical studies of coal miner absenteeism are discussed, and several strategies for 
improving miner job attendance are presented. 



INTRODUCTION 



Although estimates of the rate of absenteeism in the 
mining industry vary, most sources suggest that it is high, 
relative to other industries. Based on attendance data col- 
lected in May 1978 and May 1980, the U.S. Bureau of 
Labor Statistics reported that, among all U.S. nonfarming 
industries, mining was the highest in terms of the propor- 
tion of hours lost to absences (53, 56). 2 An analysis of 
absence data presented by Goodman (17) reveals the fol- 
lowing statistics concerning absence rates during 1982 at 
11 relatively large underground coal mines with unionized 
labor: Total absenteeism across these 11 mines averaged 
12.1 pet. 3 This total is composed of sanctioned absences 
(5.8 pet), nonsanctioned absences (2.2 pet), and absences 
due to sickness and injury (4.1 pet). 

Given current high rates of unemployment in the 
mining industry, absence rates in the mid-1980's are prob- 
ably not as high as they were in the preceding decade. The 
U.S. Bureau of Labor Statistics May 1985 survey found 
that absenteeism in the mining industry was 3.6 pet, 
which was lower than the corresponding percentage for 
1980 by 1.8 percentage points (55). Although the problem 
of absenteeism is not as widespread today as it once was, 
it still exists, and will continue to come back to haunt the 
mining industry from time to time, until mine managers 
learn better methods for controlling it. 



iResearch psychologist, Pittsburgh Research Center, Bureau of Mines, 
Pittsburgh, PA. 

2 Italic numbers in parentheses refer to items in the list of references at 
the end of this paper. 

3 This rate was calculated as follows: total days absent/number of days 
scheduled to work x 100. Unlike the U.S. Bureau of Labor Statistics, Good- 
man includes graduated vacation days in the numerator. He defines ab- 
sences as any days when the mine was scheduled to operate, but the indi- 
vidual did not come to work. 



Although there appear to be no published estimates of 
the cost of absenteeism in the mining industry, one can 
safely assume that, based on the estimated rates of absen- 
teeism, the costs are significant. In 1976, the labor rela- 
tions vice president for one of the largest coal companies 
reported that his company was carrying an extra 5 pet of 
labor to allow it to cope with absenteeism (60). 

It is inevitable that members of underground coal 
mining crews will occasionally be absent. Sometimes the 
crew will work without a replacement, but usually some- 
one is assigned to fill in for the missing miner. In either 
case, safety and production problems become more likely. 
Temporary replacements for regular crew members are 
relatively unfamiliar with the habits of the people who 
work in the crew, and the physical conditions and equip- 
ment in the section. 

Because they are unfamiliar with key aspects of their 
work environment, temporary replacements often either 
do things or fail to do things that increase accidents and 
that can reduce productivity. This problem is especially 
important in underground coal mining because it is a very 
hazardous work environment, and because the work per- 
formed by miners is very interdependent. 

In order to keep attendance as high as possible, it is 
important to understand as much as possible about what 
causes miners to be absent. Understanding the primary 
causes of absenteeism is a prerequisite for deciding which 
of several strategies is going to be most effective for main- 
taining a high level of attendance. Therefore, the Bureau 
of Mines conducted the research study presented in this 
paper primarily to learn more about the reasons for coal 
miners' absences. 



96 



CONSEQUENCES OF MINER ABSENTEEISM 



Most of the literature dealing with the consequences 
of miner absenteeism focuses on the effects that absen- 
teeism has on mine safety and productivity. 

EFFECTS OF ABSENTEEISM ON SAFETY 

A variety of sources have noted that absenteeism 
threatens miner safety. The Theodore Barry report (54) 
notes that absenteeism leads to short-crew sections, with 
crew members forced into unfamiliar operations and 
tasks. The report says 

In short-crew situations, section foremen often re- 
quest that one or more crew members from the previ- 
ous shift "double-back", i.e., work a second consecu- 
tive shift. Fatigue is the natural result of a 16-hour 
period of hard physical activity, and fatigue and ac- 
cidents are highly correlated in any industrial activ- 
ity. 
Snyder (51 ) notes that another common way to cope 
with absent mining crew members is for the supervisor to 
fill in for the missing crew member. She cites this practice 
as one of the reasons that the rate of fatal accidents suf- 
fered by supervisory personnel in the coal industry is sig- 
nificantly higher than the corresponding rate for mine 
production workers. She points out that supervisors who 
do this are not as familiar with the temporary work, and 
tend to be more likely to get injured while doing such jobs: 
A foreman who performs a task once in a while — 
say, to fill in for a crew member who's sick — is more 
likely to have an accident while doing it than the 
miner who does the job every day. The foreman is not 
as familiar with the job. The safe procedures don't 
come automatically. Even a foreman who used to do 
the task regularly is liable to be "rusty" when re- 
turning to it on an occasional basis. 
She also notes that when supervisors are engaged in pro- 
duction work, they do not have as much time to look out for 
the safety of other miners. 

Wilkinson (60) cites several mining company and 
union officials who have claimed that miner absenteeism 
produces unsafe working conditions. The United Mine 
Workers of America (UMWA) has even tried sending 
union representatives out to the homes of poor attenders to 
discuss the importance of good attendance. 

The Mine Safety and Health Administration (MSHA) 
recently performed a study of the differences between 
underground coal mines with high versus low rates of in- 
juries (11). It was observed that "absenteeism was much 
more of a problem at high rate mines than at low rate 
mines." The average rate of absenteeism at the 21 high- 
rate mines was approximately 16 pet. On the other hand, 
at the 19 low-rate mines, the average rate was approxi- 
mately 8 pet. 



The first empirical study of the effects of miner absen- 
teeism on accident rates was performed by Goodman (17). 
Data were collected from a sample of miners at 19 under- 
ground coal mines. The data consisted of mine daily at- 
tendance records, accident records, and detailed inter- 
views with approximately 50 miners from each mine. It 
was found that crews with poor job attendance consis- 
tently experienced slightly more accidents than other 
crews. Goodman attributes the greater incidence of acci- 
dents in these crews to the tendency for replacement work- 
ers to be relatively unfamiliar with their temporary jobs. 



EFFECTS OF ABSENTEEISM ON PRODUCTIVITY 

It is generally acknowledged that absenteeism ad- 
versely affects a mine operation's productivity. In describ- 
ing the processes by which absenteeism influences produc- 
tivity, Adkins (2) notes 

First of all absent workers simply don't produce 
much coal. In more indirect paths one can see that 
absenteeism can both increase safety problems and 
decrease the general skill level of the crews. Deteri- 
orating skill levels lower production and increase 
maintenance and down-time problems. Absenteeism 
leads to labor/management relations problems, fre- 
quently arising from attempts to discipline absent 
workers, which in turn lowers the productivity of 
both labor and management. 
Goodman (20 ) provides empirical evidence concerning 
the effect of crew size on productivity. He analyzed data 
from 81 mining crews at six underground coal mines using 
the number of tons of coal removed by a mining crew 
during a shift as the criterion variable. After using multi- 
ple regression analyses to statistically partial out the ef- 
fects of other factors (differences in equipment, physical 
conditions, etc.), crew size consistently emerged as a 
statistically significant variable in accounting for varia- 
tion in the criterion variable. This strongly suggests that 
absenteeism, which results in crews with fewer than the 
normal number of persons, results in significantly lower 
productivity. How much lower? At one of the mines, the 
marginal impact of a missing crew member on daily pro- 
ductivity was 6.3 st in development sections, and 11.8 st in 
sections engaged in pillaring. Of the six mines examined, 
the marginal impact of a missing crew member ranged 
from as low as 1 st to as high as 17.5 st. 

In conclusion, it appears that miner absenteeism is 
generally considered to be an important cause of accidents 
and low productivity. However, with the exception of 
Goodman (1 7, 20 ), there appears to be very little empirical 
evidence concerning these assumptions. 



97 



CAUSES OF MINER ABSENTEEISM 



As was true about research on the consequences of 
miner absenteeism, there appears to be considerable spec- 
ulation about the causes of miner absenteeism, but little 
empirical evidence. Only two empirical studies of the 
causes of miner absenteeism have been performed (Good- 
man (17) and Peters and Randolph (44)). 

As previously mentioned, Goodman collected data 
from a sample of miners at 19 underground coal mines. 
The data consisted of mine daily attendance records and 
detailed interviews with approximately 50 miners from 
each mine. Goodman's (17) findings concerning the types 
of factors that appear to contribute to miner absenteeism 
include the following: 

Illnesses and injuries are the most commonly cited 
causes of absence. 

Off-the-job activities that miners need or want to do 
(e.g., family, hunting) are also commonly cited. 

Negative job factors that might cause miners to avoid 
work are not frequently mentioned sources of absences. 

Miners holding down another job are consistently ab- 
sent more than their coworkers. 

An organization's absence control policy and the degree 
to which that policy is consistently implemented within 
the workforce is a significant determinant of attendance. 

Most miners do not feel highly pressured to produce — 
but those who do feel such pressure have higher absence 
rates. 

Demographic factors, such as age, seem to be related to 
absenteeism. However, the effect of demographics on ab- 
senteeism varies greatly among mines. 

Most miners report that they would rather have more 
time off than more money. This suggests that the desire for 



time away from work is one of the more important forces 
contributing to absenteeism. 

Based on prior studies of absenteeism and what is 
known about the coal mining industry, Peters and Ran- 
dolph (44 ) developed a model of factors that appear likely 
to influence coal miners' rates of absenteeism (see figure 
1). The predictions from this model were empirically 
tested on a sample of 63 underground miners from a west- 
ern Virginia coal mine. Miner absenteeism rates during a 
recent 12-month period were used as the criterion vari- 
able, and data on miners' demographic characteristics and 
attitudes about their work were used as predictors. 

Nine different indexes of absenteeism were con- 
structed from the attendance data. Using multiple regres- 
sion analyses, a model similar to the one portrayed in 
figure 1 was used to account for variance in the nine in- 
dexes of absences. Although the model usually accounted 
for a substantial amount of the variance (ranging for 44 to 
79 pet) in the nine indexes of absenteeism, it emerged as 
a statistically significant (p <0.050) predictor of only one 
absenteeism index. This absenteeism index measured the 
number of consecutive work days that miners were away 
from their job whenever they used days that the UMWA 
contract refers to as graduated vacation days or paid per- 
sonal days. 4 Absences due to these reasons were analyzed 
separately because, in contrast to absences caused by ill- 
ness or injury, absences for these reasons are much more 
likely to be within the miner's ability to control. 



4 See Peters and Randolph (44 ) for a complete discussion of the other 
indexes and how they are analyzed. 



Transportation problems 
Health status 
Safety 



Fear of 
underground 

Downtime- 




Shift- 



S/W coworkers 

-S/W equipment 

S/W working conditions 
-S/W opportunities for social acts 

S/W advancement opportunities^ 

S/W job content 



S/W supervision closeness- 
S/W supervision fairness- 
S/W pay 



Control system permissiveness- 
Local unemployment rate- 
Kinship responsibility- 
Norms — 



Personal work ethic 



Attendance^ 
motivation 



Absence 



Desire to avoid 
income loss 



KEY 

+ Positive association 
- Negative association 



Figure 1 . — Absenteeism model. (S/W— satisfaction with. The hypothesized relation between the variables "Shift" and "Satisfaction 
with opportunities for social acts" is that miners who work daytime shifts are more satisfied with their opportunities for participating 
in social activities than those who work other shifts.) 



98 



Two variables were found to be statistically signifi- 
cant predictors of the duration of absences taken as gradu- 
ated vacation leave or personal days: level of satisfaction 
with supervisor and level of satisfaction with pay. This 
means that, when they had a choice about being absent, 
miners who were relatively dissatisfied with their pay 
and/or the way their supervisor treated them, were in- 
clined to stay away from work for longer periods of time 
than miners who were more satisfied with their pay and/or 
the way their supervisor treated them. 

Why would miners who are dissatisfied with their pay 
and/or their supervisor tend to be absent for relatively 
long spells? The answer is not exactly clear. One explana- 



tion, derived from equity theory (i ), is that these long 
spells of absence may stem from a reluctance to resume 
participating in an unfair employment relationship. Em- 
ployees who believe that their employer or supervisor is 
unfair (and who cannot find employment elsewhere) are 
likely to experience negative affective reactions, such as 
feelings of frustration or anger. Employees who are having 
such undesirable reactions may experience temporary re- 
lief from them whenever they are away from work. Be- 
cause returning to work is associated with an intensifica- 
tion of these undesirable feelings, these employees may 
tend to stay away from work for relatively long periods of 
time. 



A MODEL OF THE CAUSES OF MINER ABSENTEEISM 



Much research has been performed on the causes of 
employee absenteeism among nonmining employees. 
Through use of the findings from prior research on the 
absenteeism of miners and other types of employees, a 
conceptual model of the factors that contribute to absen- 
teeism among miners was generated (fig. I). 5 

Predictions regarding the direction of the association 
between the variables in the model are indicated by plus 
and minus signs (fig. 1). Miner attendance behavior is 
hypothesized to be influenced most directly by perceived 
ability to attend and motivation to attend. 



predictor of coal miner attendance. The relationship be- 
tween these two variables should be further investigated. 
Therefore, it is hypothesized that job satisfaction is posi- 
tively related to miner attendance motivation. For practi- 
cal as well as theoretical reasons, it would be valuable to 
know which specific facets of job satisfaction are most 
strongly related to absenteeism. Therefore, the following 
variables are also included: satisfaction with safety, with 
coworkers, with equipment, with working conditions, with 
opportunities for social activities, with advancement op- 
portunities, with job content, with supervision, and with 
pay. 



PERCEIVED ABILITY TO ATTEND 

Miner ability to attend is obviously an important fac- 
tor in actual attendance. However, perceived ability may 
be more important than actual ability. That is, a snow- 
storm or a bad cold may or may not limit one's ability to 
come to work. What is important is how the individual 
treats the event and how he or she interprets its impact on 
ability to attend. This is why the model contains a dotted 
line going from attendance motivation to perceived ability 
to attend. In addition to attendance motivation, other im- 
portant determinants of perceived (and actual) ability to 
attend are transportation problems, health status, and 
safety. 

ATTENDANCE MOTIVATION 

The model identifies eight direct determinants of 
miner attendance motivation: overall job satisfaction, sat- 
isfaction with time for social activities, job involvement, 
distributive justice, absenteeism control system permis- 
siveness, desire to avoid income loss, attendance norms, 
and personal values. Each of these are discussed in the 
following sections. 

Overall Job Satisfaction 

Although many researchers have found that job satis- 
faction is related to attendance, Goodman's (1 7) study sug- 
gests that job satisfaction may not be an especially good 



5 A summary of the absenteeism research findings for mining and for 
nonmining employees is presented in Peters and Randolph (44). The report 
also contains a more detailed discussion of the variables in the absenteeism 
model presented in this paper. 



Satisfaction With Opportunities for Family-Social 
Activities 

A significant portion of the time most underground 
coal miners spend at work is during evening and night 
shifts. Because miners who must work these shifts may 
have limited opportunities to do things they enjoy with 
their family and friends, they may be especially likely to 
be absent from time to time so that they can take part in 
such activities. The rotating shifts used by some mining 
companies can also be disruptive to a miner's social life. 
Therefore, it is hypothesized that those who work non- 
daytime or rotating shifts (1) have lower levels of overall 
job satisfaction, and (2) have lower levels of motivation to 
attend work. 

Job Involvement 

Job involvement has been found to be positively re- 
lated to attendance. According to most definitions, the key 
determinants of job involvement are aspects of job content, 
supervision, and career advancement opportunities. To 
the extent that the job involves work that allows the miner 
to feel that he or she is making important contributions to 
the organization, to experience a sense of personal 
achievement, and to make use of his or her skills and 
abilities, the miner will be involved in his or her job. To the 
extent that miners are supervised in such a way that they 
are typically allowed to influence what goes on at their 
worksite, set their own work pace, actively participate in 
decisions about their work, and use creativity in solving 
problems, they will be involved in their job. To the extent 
that miners perceive that their career advancement oppor- 
tunities with their current employer are good, (i.e., that 



99 



they are sufficiently competent and successful to be given 
the opportunity to perform more important and more diffi- 
cult jobs in the future) miners will be involved in their 
current jobs. Therefore, it is hypothesized that (1) miner 
satisfaction with job content, freedom from close supervi- 
sion, and career advancement opportunities are all posi- 
tively related to job involvement, and (2) the greater the 
miner job involvement, the greater is the motivation to 
attend work. 



Distributive Justice 

Equity theory, as originally proposed by Adams (1 ), 
considers employee perception of fair treatment by the 
employer to be a major determinant of the motivation to 
make contributions of time, energy, ingenuity, etc., to the 
job. The theory holds that one of the ways employees may 
respond to actual or perceived unfair treatment is to re- 
duce their job contributions. One obvious way to accom- 
plish this reduction is to attend work less often. Therefore, 
it is hypothesized that a significant determinant of miner 
attendance motivation is the extent to which they perceive 
that they are treated fairly by their employer, i.e., the 
degree to which distributive justice is perceived to exist in 
the employee-employer exchange. 

One important determinant of distributive justice is 
miner perception about the adequacy of wages, benefits, 
and other economic rewards the employer provides. An- 
other important determinant is the degree to which min- 
ers perceive that their supervisor allocates work assign- 
ments, resources, and various nonmonetary rewards and 
punishments in an equitable manner. Therefore, it is hy- 
pothesized that miners' perceptions of distributive justice 
are determined by their satisfaction with their economic 
rewards and the degree to which they perceive that their 
supervisor treats them fairly. 



Absence Control System Permissiveness 

Absence control systems involve those policies and 
procedures used by the organization to encourage attend- 
ance. The permissiveness is the degree to which absen- 
teeism is accepted by the organization. The central idea of 
this concept is frequent absence without consequence (42 ). 
An organization or subunit in which numerous casual ab- 
sences result in little or no apparent adverse consequences 
would be highly permissive toward absenteeism. Empiri- 
cal support for the hypothesized direct causal relationship 
between permissiveness and absenteeism has been re- 
ported by Seatter (50), Rhodes and Steers (47), Winkler 
(61 ), and Popp and Belohav (46). Therefore, it is hypothe- 
sized that the permissiveness of the mine's absence control 
system is positively associated with absenteeism. 



Desire to Avoid Loss of Income 

Miners differ in the extent to which they desire to 
avoid losing income. The strength of this desire is hypoth- 
esized to be positively related to their attendance motiva- 
tion. Two determinants of miner desire to avoid income 
loss are the local unemployment rate and kinship respon- 
sibilities. 



Local Unemployment Rate 

Economic and job-market conditions often place con- 
straints on an employee's ability to change jobs. As a re- 
sult, in times of high unemployment, there may be in- 
creased pressure to maintain a good attendance record for 
fear of losing one's job. Several studies have found an in- 
verse relationship between changes in unemployment lev- 
els and subsequent absence rates (6-7, 10). Therefore, it is 
hypothesized that local unemployment rates are positively 
related to miner desire to avoid income loss, and to attend- 
ance motivation. 

Kinship Responsibility 

Another determinant of miner desire to avoid income 
loss is the degree to which miners are responsible for sup- 
porting family members or other dependents. In contrast 
to single miners with fewer financial responsibilities, min- 
ers who must support a family are probably going to be 
less willing to take the chance of losing some of their pay 
(or getting fired) because they take off work for reasons 
that the company considers unexcusable. Therefore, it is 
hypothesized that kinship responsibility is positively re- 
lated to miner desire to avoid income loss, and to attend- 
ance motivation. 

Norms 

Several authors have suggested that another impor- 
tant determinant of attendance motivation is the degree to 
which the immediate work group views one's absences 
from work negatively (14, 27, 36, 52). Therefore, it is hy- 
pothesized that miner attendance motivation is positively 
related to the degree to which the crew views absences 
among its members negatively. 6 Although it has not been 
formally tested, it would also seem likely that miner 
attendance motivation is significantly affected by the 
norms of miners' families, relatives, and close friends re- 
garding the importance of job attendance. 

Personal Values 

Finally, the miner's personal value system may be an 
important determinant of job attendance. Prior research 
suggests that a strong personal work ethic is closely re- 
lated to attendance (12, 15, 26). Therefore, it is hypothe- 
sized that miner attendance motivation is positively re- 
lated to the degree to which miners have a strong personal 
work ethic. 

It is also important to consider personal values con- 
cerning nonwork activities. Some absence may be at- 
tributable to the value miners place on their nonwork 
activities. In his study of the Rushton Mine, Goodman (16) 
found that, although they view their work as important, 
miners usually did not feel that their job was the central 
part of their life; home and other nonwork activities were 
more central. This observation suggests that the values 
miners place on nonwork interests (e.g., hunting, hobbies, 
family activities) may be an important reason for some of 
their absences. 



6 However, for various reasons it has been argued that the amount of peer 
group pressure on miners to attend work is minimal (2, 51, 56). 



100 



STRATEGIES FOR REDUCING ABSENTEEISM 



In general, strategies for reducing absenteeism should 
fit the specific causes of absenteeism. The causes of absen- 
teeism stem from the employee's inability or unwilling- 
ness to attend work. However, before proceeding to discuss 
potential solutions to each of the specific causes, one 
generic strategy for preventing high absenteeism will be 
discussed; i.e., improving procedures for hiring new em- 
ployees. 



IMPROVING HIRING PROCEDURES 

Research by Breaugh (8) and Keller (30) suggests 
that prior attendance records could be a very simple but 
effective device for evaluating prospective new employees. 
Both studies found that employees' prior absenteeisms 
were a statistically significant predictor of their future 
absenteeism. 

Realistic job previews can be a complementary mech- 
anism to good selection practices. It is assumed that a 
person who chooses to accept an employment offer based 
on a complete and realistic job description is likely to have 
greater commitment to that job. The goals of the preview 
are (1) to ensure a good match between the capabilities 
and needs of the applicant and the requirements of the job 
and company; and (2) to be sure that the applicant has a 
good picture of both the positive and negative aspects of 
the job (58). This seems particularly important in the min- 
ing context if the applicant has no underground mining 
experience. Although job previews have been empirically 
demonstrated to reduce turnover (58 ), there appears to be 
no research concerning their effects on attendance. 

As previously mentioned, it is important to consider 
the specific causes of employees' absences. These specific 
causes can be thought of as stemming from the employee's 
inability or unwillingness to attend work. 



OVERCOMING INABILITY PROBLEMS 

The major reasons employees are unable to attend 
work are physical health problems, mental health prob- 
lems, occupational hazards, and transportation problems. 
The remainder of this section presents strategies for re- 
ducing each of these types of barriers to miner job attend- 
ance. 

Physical Health Problems 

Illness is widely recognized as the most important 
cause of absenteeism (22-24, 38), accounting for from one- 
half to two-thirds of all employee absence (40). In the 
mining industry, injuries are a particularly important 
cause of employee absence. According to MSHA, injuries 
accounted for an average of 1.42 pet of the total days of 
work missed by the employees of underground coal mining 
operations during the years 1980-84 (57). The percentages 
per year ranged from 1.29 to 1.59 pet. Of the various types 
of work-related injuries suffered by miners, back injuries 
account for a far greater amount of lost time than any 
other single type. Back injuries account for approximately 
31 pet of all the workdays underground coal miners miss 
because of work-related injuries (43 ). Thus, it appears that 



illnesses and injuries account for a substantial portion of 
the total time coal miners miss work. 

A worker who is more susceptible to illness or injury, 
or one who has certain chronic illnesses or injuries, is more 
likely to be absent. If the source of absenteeism was from 
personal health problems, there could be a variety of possi- 
ble strategies to deal with this cause. Better selection pro- 
cedures could eliminate chronic cases. Making in-house 
medical services, special testing programs (e.g., for hyper- 
tension), and health education programs available is an- 
other possible response to personal health problems. Un- 
fortunately, other than a study by Hedja, Smola, and 
Masek (25), there is little or no empirical evidence con- 
cerning the effectiveness of this type of strategy for min- 
ers. (Hedja, Smola, and Masek found that influenza vacci- 
nations and daily doses of vitamin C produced a significant 
reduction in absences due to illness at Czechoslovakian 
coal mines.) 

Mental Health Problems 

Mental health problems include chronic emotional 
problems (e.g., depression) and other forms or symptoms of 
emotional illness, such as alcoholism and drug abuse. A 
recent study indicates that these causal factors do appear 
among employees in the coal industry, and they do seem to 
have some impact on absenteeism and performance (18). 

Selection and employee assistance programs (EAP's) 
are the most traditional methods for dealing with mental 
health problems. The first strategy attempts to improve 
the quality of those mechanisms that screen out workers 
who have mental health problems that interfere with job 
performance. EAP's are designed to provide diagnosis, re- 
ferral, treatment, and followup for workers with these 
types of problems. There are many types of EAP's. While 
some are broad brush, others are specific (e.g., alcoholism); 
some only provide diagnostic and referral services, and 
others also include treatment (see Goodman (18) for fur- 
ther details). The assumption behind these programs is 
that the removal of these emotional problems will enhance 
worker attendance, safety behavior, and productivity. 

Occupational Hazards 

Because accidents are an obvious cause of one kind of 
absenteeism, an effective company safety and health pro- 
gram is an important deterrent to absenteeism. In two 
studies it has been found that workers who feel they are 
being exposed to dangerous or unhealthful working condi- 
tions have substantially higher absence rates than other 
workers (3, 37). Allen (3) argues that, not only do haz- 
ardous working conditions cause absences directly, i.e., 
through lost-time injuries, such conditions also cause high 
absenteeism indirectly — employees wish to avoid their 
workplace because it is perceived as a threat to their safety 
and health. For a discussion of the characteristics of effec- 
tive safety programs for the mining industry, see reference 
45. 

Transportation Problems 

Factors such as driving distance to work, bad roads, 
weather, or other transportation problems, are related to 
absenteeism. Such problems are common in the mining 



101 



industry. Miners are often located in isolated rural areas 
and must drive long distances to get to work. Some compa- 
nies in mining and nonmining industries have provided 
transportation (e.g., company buses) to reduce absen- 
teeism. Unfortunately, there are no cost-benefit analyses 
to indicate the effect of these procedures. 

Thus far, only the reasons employees are unable to 
attend work have been considered. The next section dis- 
cusses specific reasons why employees may be unwilling to 
attend work. 

OVERCOMING MOTIVATIONAL PROBLEMS 

As discussed earlier, research suggests that there are 
many reasons why employees who are able to attend work 
are, nevertheless, sometimes unwilling to attend work. It 
is important to consider the sources of their unwillingness. 
The sources can be either positive features of the nonwork 
environment or negative features of the work environ- 
ment. Goodman's (17) study suggests that the most impor- 
tant causes of miner absenteeism are generally attractive 
features of the nonwork environment, and that in general, 
negative features of the work environment are not respon- 
sible for miner absenteeism. The remainder of this section 
presents strategies for increasing miner motivation to at- 
tend. These strategies are giving feedback, training for 
supervisors and employees, job design, and incentive pro- 
grams. 

Giving Feedback 

Measuring absenteeism and posting attendance infor- 
mation may reduce absenteeism. Latham and Napier (35) 
state that 

from the standpoint of motivation, measurement in 
itself may be the most highly effective, underused, 
and deceptively straight-forward approach available 
for increasing attendance. The process is effective 
because "what gets measured gets done." The simple 
act of putting a measure on something focuses atten- 
tion on that area. 
They report several studies that used publicly re- 
ported attendance information to significantly decrease 
absenteeism. Latham and Napier (35) admit that this in- 
tervention requires some increase in clerical-computer 
costs, but claim that these costs are likely to be trivial in 
comparison to the gains realized from significantly higher 
attendance rates. 

A study conducted at Parkdale Mills, Inc., nicely illus- 
trates the effectiveness of this appraoch (39). Prior to the 
study, people who were absent were reprimanded. Those 
who had good attendance records received no comments. A 
15-week baseline showed that attendance averaged 86 pet. 
At the end of the baseline period, a daily attendance chart 
was placed in the work area. A blue dot was placed on the 
chart beside the name of each person who was on the job. 
A red dot was placed beside the name of each person who 
was off the job. A person who had been absent was wel- 
comed back to the job by the supervisor. No oral or written 
reprimands were given. The supervisor maintained this 
graph daily. In addition, he posted a weekly attendance 
graph that showed the percentage of people who attended 
the job each day. From a baseline average of 86 pet, attend- 
ance averaged 94.3 pet for the following 9-week period. 
The cost of the materials for this program was less than 
$10. 



Training 

Training can be an important strategy for reducing 
absenteeism. Training for this purpose has been conducted 
for supervisors and for employees. 

Training for Supervisors 

The Bureau of National Affairs (BNA) (9) survey 
found that, although supervisors in 82 pet of the firms are 
charged with maintaining daily attendance records, only 
42 pet of the companies train supervisors in absence con- 
trol. The BNA report indicates that the firms that train 
their supervisors on this topic provide information on tech- 
niques for counseling employees, recognizing attendance 
problems, and methods for handling verbal reprimands 
and other disciplinary procedures. Although a few compa- 
nies educate their supervisors in absence control through 
one-to-one consultation with a personnel department staff 
member, most provide the information through supervi- 
sory meetings, seminars, or films. 

One employer's approach to supervisory training in 
absence control includes a booklet describing the supervi- 
sor's role in sick leave administration. The booklet de- 
scribes types of health problems, circumstances for which 
sick leave may be taken, and instructions for processing 
sick leave requests. A major intent of this publication is to 
provide a set of uniform guidelines so that all supervisors 
will be following the same standards in making sick-leave 
decisions. 

Latham and Napier (35) state that supervisors are a 
key to keeping attendance rates high. 

It is they who should be responsible for keeping at- 
tendance records, so that a high attendance rate can 
be rewarded and a low attendance rate can be cor- 
rected. This is not likely to be done if the attendance 
data are buried in time cards, if the supervisor is 
continually second-guessed by others on judgments 
regarding the "why's" underlying an absence, if the 
supervisor is not trained in how to focus on problems 
rather than personalities, and if the rules regarding 
attendance are vague and subject to many interpre- 
tations. 
There is very little empirical evidence concerning the 
effects of supervisory training on absenteeism. However, 
on a commonsense basis, training the supervisor to deal 
with absenteeism seems an important strategy in reduc- 
ing absenteeism because the supervisor is the person who 
deals first with the absentee problem. Research by Wexley 
and Nemeroff (60 ) suggests that having supervisors par- 
ticipate in role-playing exercises related to violations of 
organizational attendance rules can result in decreased 
absenteeism. 

Adkins (2) also stresses the importance of making 
sure that supervisors understand how to respond to their 
subordinates' absenteeism. 

When a problem individual begins to show up in the 
records, someone who knows him (most likely the 
immediate supervisor) should talk with him about it 
face to face before he gets letters on company sta- 
tionery. The latter only breed hostility and resent- 
ment. Consistent and even-handed administration 
of the program, particularly the disciplinary aspects, 
is likely to be more important to worker acceptance 
than are the details of the program. 



102 



Training for Employees 

Research on an orientation training program devel- 
oped by Rosen and Turner (48) suggests that it is possible 
to achieve attendance rates for "hard-core hires" that are 
as good as the rates for stable employees, i.e., those who 
had met normal hiring criteria. Goodman (17) claims that 
it is important to supplement orientation training with 
periodic training about the absentee control plan. He 
claims that discussing the plan in an orientation session 
may have a short-term effect, but will not affect absen- 
teeism over time. 

Job Design 

There is considerable research on the impact of job 
characteristics on worker satisfaction and absenteeism. 
One of the more important determinants of employee mo- 
tivation to attend appears to be level of job involvement (4, 
28-29). According to Katz and Kahn (29), in order to 
arouse and maximize job involvement, the job must pro- 
vide sufficient variety, sufficient complexity, sufficient 
challenge, and sufficient exercise of skill to engage the 
abilities of the employee. Katz and Kahn argue further 
that job involvement occurs to the extent that employees 
(1) participate in important decisions about group objec- 
tives, (2) contribute to group performance in a significant 
way, and (3) share in the rewards of group accomplish- 
ment. 

In Kanugo's (28) review of research on the conse- 
quences of job involvement, she concludes, "On the basis of 
the existing evidence, it seems reasonable to assume a 
negative relationship between job involvement and absen- 
teeism, but the evidence is limited to only a few studies." 

Job enrichment and the creation of autonomous work 
groups appear to be effective strategies for increasing job 
involvement. According to Filley, House, and Kerr (13), 
job enrichment occurs when any of the following types of 
changes occur: employees are supervised less closely, 
given greater influence over their environment, given 
greater freedom to control their own work, and given 
greater opportunity to plan for the future and to partici- 
pate in planning matters that affect their jobs. In their 
review of attempts to use these strategies in various types 
of organizations, Goodman and Lawler (19) note that 
there has been a trend toward experimenting with new 
forms of job and organizational design over the past 10 yr, 
and that these interventions usually result in lower levels 
of absenteeism. 

Job enrichment is generally thought to result in 
greater intrinsic motivation to work. Adkins (2) believes 
that the key to improving miner attendance is through 
increasing intrinsic rewards. 7 He writes, "Intrinsic re- 
wards that serve to improve the quality of work life and 
level of job satisfaction are more likely to improve attend- 
ance than are strategies based on extrinsic rewards or 
punishments." 

The primary effect of an autonomous work group is to 
increase the employee's opportunity to participate in deci- 
sions affecting his or her job. Goodman (16) conducted an 
empirical evaluation of the effects of an autonomous min- 
ing crew structure at the Rushton coal mine. He found 



7 Intrinsic rewards result directly from effort and effective performance 
'usually these take the form of enjoyment with the effort itself or satisfac- 
tion with goal attainment). Extrinsic rewards are those controlled by 
others. 



that, in comparison to control group crews (who kept the 
traditional pattern of centralized decisionmaking), absen- 
teeism was reduced to a significantly lower level in the 
autonomous mining crews. This suggests that increasing 
the degree to which miners are allowed to participate in 
decisions affecting their job can significantly improve 
their attendance. 

Incentive Programs 

Three general types of incentive programs have been 
used to reduce absenteeism: positive reinforcement pro- 
grams, negative sanctions programs, and mixed pro- 
grams — ones that used positive and negative incentives. 

Positive Reinforcement Programs 

Positive reinforcement programs provide some re- 
ward for lower absenteeism. Steers and Rhodes (52) re- 
view of research on these programs indicates that rein- 
forcers such as bonuses, participation in a lottery, 
participation in a poker hand, food credit reimbursement 
for unused sick leave, and desirable work schedules can 
lead to a reduction in absenteeism. While there are other 
programs using positive reinforcement that did not lead to 
a reduction in absenteeism, the majority of the empirical 
evidence supports the effectiveness of positive reinforce- 
ment programs. 

One criticism of these programs is that they are not 
always cost effective. Kempen (31) notes that they are 
often not cost effective because all the perfect or near- 
perfect attenders receive the money (or reward), even 
though they cannot improve their attendance. To avoid 
this cost, Kempen suggests that two questions be asked: 
(1) What privileges would people like to have that they do 
not have now? (2) What do they find irritating or aversive 
in the work setting? The answers to these questions pro- 
vide a list of possible rewards for reinforcing attendance 
that may not be costly to the organization. Examples of 
nonmonetary privileges for good attendance that have 
been tried include freedom from punching time clocks, 1 or 
2 excused days off without pay, and immunity from disci- 
plinary action for a year related to absence taking. 

Negative Sanctions 

Programs based on negative sanctions are built 
around absentee control plans. Control plans usually 
specify stages, levels of absenteeism permitted, penalties, 
and continuous attendance necessary to work oneself off 
the absentee control plan. Basically these plans identify a 
series of stages of varying forms of punishment. For exam- 
ple, absenteeism at a particular level would lead to a 
warning letter. Subsequent levels of absenteeism would 
lead to a suspension. Continued absenteeism would lead to 
dismissal. 

According to Steers and Rhodes (52) and Baum (5), 
the literature is characterized by divided opinions and con- 
flicting findings concerning the efficacy of sanctions in 
reducing absenteeism. Much of the opposition to the use of 
sanctions is based on two grounds: (1) behavior modifica- 
tion techniques based on positive reinforcement of desired 
behaviors (coming to work regularly) are more suitable 
and effective in dealing with absenteeism; (2) sanctions 
based on the use of disciplinary procedures (punishments) 
tend to produce undesirable side effects that are as objec- 
tionable as the behavior of primary interest. For example, 



103 



Nicholson (41) found that rigorously enforced sanctions 
caused workers to resort to longer, medically related ab- 
sences to escape the consequences of the disciplinary sys- 
tem; the overall level of days lost was not changed by the 
clampdown. 

In contrast, Baum (5) found that the strict enforce- 
ment of the control policy had no discernible effect on 
either long-term illnesses or contractual absences. A well- 
designed study by Baum (5) suggests that negative sanc- 
tions can significantly improve the attendance of chroni- 
cally absent employees. The study employed a 
nonequivalent control group design since it was not possi- 
ble to randomly assign subjects to the treatment and con- 
trol groups. Absenteeism was defined as the number of 
days the worker failed to report to the job when work was 
scheduled excluding long-term illnesses and contractual 
absenteeism. 

In the experimental group, management used the fol- 
lowing six-step procedure in all cases of unauthorized ab- 
senteeism: (1) detailed attendance records would be kept 
by the worker's supervisor, (2) written excuses from legit- 
imate outside sources would be required for unauthorized 
absences, (3) questionable excuses would be independently 
investigated, (4) management would personally counsel 
all workers with unauthorized absences, (5) the existing 
progressive discipline system would be used to penalize 
excessive absenteeism, and (6) updated discipline and at- 
tendance records would be maintained on all workers. The 
managers in the two comparison departments continued 
with the existing attendance policy that simply delegated 
the responsibility for attendance control to the immediate 
supervisor. 

A pre-post measure of absenteeism served as the crite- 
rion. The independent variables were casual versus strict 
enforcement of the attendance control policy and three 
levels of absence groups (high, medium, and low). It was 
found that, in comparison to high absence workers in the 
control group, absenteeism among high absence workers 
in the experimental group was reduced by a significantly 
larger extent (p <0.05). The chronically absent workers 
who were subject to the attendance control policy im- 
proved their attendance an average of 7 days per year over 
the comparison group. The intervention produced no 
change in the absence rates of the two groups of more 
regular attenders. However, significant improvements in 
these two groups were not considered to be as important as 
improvements in the group of chronically poor attenders. 
Although the group of chronic absentees was only 25 pet of 
the sample, they accounted for 56.5 pet of the total days 
lost. 

Mixed Consequences Plans 

Plans that include both positive incentives for attend- 
ance and negative sanctions for absence have been devised 
and empirically tested (21, 32-34). These mixed conse- 
quence plans were generally found to be quite effective at 
reducing absenteeism. The design of these mixed plans 
varied considerably. Those who wish to find out the details 



of each of these plans are referred to the four articles cited. 
Several leading researchers and practitioners have spoken 
highly of this type of plan, e.g., Latham and Napier (35), 
Steers and Rhodes (52), Baum (5), and Adkins (2). 

Participation in Incentive Plan Design 

Two nonmanagement groups are sometimes included 
in the design of incentive plans to improve attendance: 
employees and unions. Research suggests that their par- 
ticipation can help to ensure the success of the plan. 

Employee Involvement 

Latham and Napier (35) argue that greater involve- 
ment of employees in designing an absentee system may 
increase their motivation to adopt the system as their own. 
If the absentee system is seen as their own construction, 
they will more likely follow its rules. Some of the ways to 
initiate a program of employee involvement in absen- 
teeism are to (1) provide information about absenteeism 
rates, costs of absenteeism, and the consequence to the 
worker, in terms of job security, of high absentee rates; the 
point is, absenteeism must be perceived as a problem; (2) 
provide an opportunity for employees to participate in the 
design of an absenteeism program that will create positive 
incentives for attendance and punishments for high absen- 
teeism; and (3) provide an opportunity for employees to 
monitor absenteeism over time and to monitor the effec- 
tiveness of their program to reduce absenteeism. 

Scheflen, Lawler, and Hackman (49) performed a 
well-designed field experiment on the effects of employee 
participation in the development of pay incentive plans to 
increase attendance. Three groups of building mainte- 
nance employees developed their own incentive plans to 
reward high attendance, and identical plans were then 
imposed by company management in two other work 
groups. A significant increase in attendance was found 
during the first 16 weeks following implementation of the 
plans only in the groups where the plans were participa- 
tively developed. Attendance rates were not significantly 
altered in the groups subjected to the management- 
imposed plans. A folio wup evaluation conducted 1 yr after 
the original plans had been installed revealed that attend- 
ance was still higher in the groups that had been allowed 
to participate in designing their own plan. 

Union Involvement 

Programs developed by union and management may 
be another way to deal with absenteeism. As previously 
mentioned, absenteeism can cause grievances. Therefore, 
both union and management have a stake in dealing with 
this issue. Some unions and companies (e.g., United Auto 
Workers and General Motors) have established joint com- 
mittees at the national and local levels to seek ways to 
deal with absenteeism. There are no data available to as- 
sess the effectiveness of joint labor-management efforts on 
absenteeism. 



104 



SUMMARY 



High absenteeism among underground miners is a 
threat to miner safety and seriously hampers productivity. 
Therefore, it is important to understand what factors lead 
to miner absenteeism and what can be done to control it. 
There have been two attempts to empirically determine 
the causes of miner absenteeism, and numerous attempts 
to determine the causes for absenteeism among employees 
of other industries. Using the findings from these studies 
and what is known about coal miners and the mining 
industry, a conceptual model of the factors that produce 
absenteeism among coal miners was generated. This 
model posits that the factors that determine whether 
underground miners come to work are transportation 
problems, health status, safety, job involvement, distribu- 



tive justice, absence control system permissiveness, desire 
to avoid income loss, attendance norms, personal values, 
and satisfaction with various aspects of the job. These as- 
pects of job satisfaction include safety, coworkers, equip- 
ment, working conditions, opportunities for social activi- 
ties, advancement opportunities, job content, closeness of 
supervision, fairness of supervision, and pay. 

Several specific strategies for controlling miner ab- 
senteeism are identified and discussed. These strategies 
are designed to decrease absenteeism by (1) improving 
hiring procedures, (2) removing obstacles that make em- 
ployees unable to attend work, and (3) increasing miner 
motivation to attend work. 



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106 



EXAMINATION OF THE DESIGN OF BONUS PLANS 
IN UNDERGROUND MINING 



By Paul S. Goodman 1 



ABSTRACT 



This paper provides an analysis of the modal bonus plans in underground mining. 
The basic structure of the plans is presented in terms of 15 different decisions. The 
modal plan is then subjected to a theoretical analysis, a literature-based analysis, and 
an empirical analysis. The basic conclusion is that the modal plan in the industry is not 
strong in eliciting high motivation and performance. Conditions within a mine that are 
favorable to such a plan and that should elicit success are presented. 



INTRODUCTION 



The purpose of this paper is to examine the effective- 
ness of wage incentive plans or bonus plans in under- 
ground coal mining. In this paper, the structural features 
of bonus plans will be examined. That is, any bonus plan 
represents a series of decisions. The results of these deci- 
sions create the specific design or structure of the plan. By 
analyzing the form of these plans, certain aspects of their 
effectiveness can be uncovered. These dimensions examine 
the major decisions a designer must consider in formulat- 
ing a plan. The paper begins this way to give the reader a 
picture of a bonus plan that can be referred to while mov- 
ing through the analysis. 

Decision 1: Bonus Calculation Period. — A bonus can 
be calculated at any time period. A bonus could be paid out 
daily, weekly, monthly, quarterly, or at some other time 
period. The selection of the time period is related to the 
effectiveness of the plan. 

Decision 2: Bonus Payout Period. — A bonus can be 
paid out at the same time it is calculated, weekly, 
monthly, etc., or, the bonus could be paid out at a time 
different from the calculation payment. For example, the 
bonus could be calculated on the weekly basis, but the 
payout would be on a monthly basis to economize on ad- 
ministration activities. 

Decision 3: Form of Payout. — The bonus can be in- 
cluded in a regular payroll check or in a separate check. 

Decision 4: Bases of the Plan — Critical Criterion. — 
Plans can be designed around a number of organizational 
effectiveness dimensions. 

1. Production. Almost all plans reviewed will be based 
on increases in production 

2. Safety. Incentive plans can be based solely on im- 
provements in safety or include improvements in safety 
and production. 



'Professor of industrial administration, Graduate School of Industrial 
Administration, Carnegie Mellon University, Pittsburgh, PA. 



3. Absenteeism. Incentive plans can be based on reduc- 
tion in absenteeism. 

4. Supply costs. Incentive plans can include reduction of 
supply costs, a base in calculating a bonus. 

Decision 5: Designing the Production Bonus For- 
mula. — A critical feature in any plan is designing the 
formula for calculating production gains. While there are 
many possible formulas, tons per week, adjusted by the 
workforce, compared to a standard represents one com- 
monly used production formula. 

Decision 6: Selection of the Standard. — All bonus 
plans are based on comparing actual performance to a 
standard. So the selection of the standard is very impor- 
tant in the overall functioning of the plan. A standard can 
be derived from historical data or expected budget esti- 
mates. 

Decision 7: The Use of Single Versus Multiple Stand- 
ards. — A unique feature of underground coal mining (ver- 
sus other types of industries) is that there are frequent 
variations in physical conditions on production. Since 
physical conditions are outside the workers control, the 
question is whether different standards should exist for 
different conditions. 

Decision 8: Determining the Safety Formula. — The 
safety formula could be based on some combination of fre- 
quency and severity of accidents and violations. 

Decision 9: Selecting Safety and Violation Stand- 
ards. — As is true of production formulation, it is necessary 
to select standards for accident rates and for violations. 

Decision 10: Source of Funds for Production and 
Safety. — If a bonus plan is based on both improvements in 
production and safety, there is an issue of whether im- 
provement in safety comes from savings only in safety or 
also from savings in production. Sometimes savings from 
improvements in safety are not large enough to have a real 
impact as a safety incentive. Still the organization wants 
to reward safety. 



107 



Decision 11: Distribution to the Company. — Whatever 
the basis of the bonus plan (e.g., production, or production 
and safety) there need to be rules about the share the 
company receives independent of its employees (manage- 
rial and hourly). The company receives a share of the 
bonus because it is the provider of capital, facilities, and 
resources. 

Decision 12: Distribution of Bonus. — The first option 
is that management and employees can have a separate 
bonus plan; the source of funds and the distribution rules 
would be separate. The second option is that the source of 
funds for labor and management would be the same but 
the distribution values for labor and management would 
differ. The third option is that labor and management 
draw from the same fund and distribute the bonus on the 
same basis. 



Decision 13: Form of Payment. — The typical form of 
payment is money. Time off is another option, or some 
combination of time off and money. 

Decision 14: Payoff Schedule. — The bonus can be paid 
off in a linear fashion or in an accelerated fashion. For 
example, in the linear fashion, a 5-pct increase may lead 
to $50 and a 10-pct increase to $100, while in an acceler- 
ated schedule a 10-pct increase may lead to a $150 bonus. 

Decision 15: Additional Organizational Arrange- 
ments. — Some incentive plans introduce a new set of orga- 
nizational arrangements to increase the likelihood of 
bonus payouts. Some companies involve employees in the 
design of the bonus plan. Others use a committee structure 
to monitor the plan, and to provide employees with an 
opportunity to present ideas to improve productivity and 
safety. 



MODAL BONUS PLANS IN UNDEGROUND COAL MINING 



In this section some empirical data on bonus plans in 
underground coal mines is presented. The purpose is to 
illustrate the modal characterization of bonus plans in 
underground coal mining as well as some of the variation. 
The objective is to use the modal characterization as a way 
of talking about bonus plans in the underground coal in- 
dustry. 

The sample consists of bonus plans from 72 under- 
ground mines. The plans were initiated during the 1981- 
84 time period. The mines are located in the eastern U.S. 
coalfields. Mine size ranges from less than 100 to 500 em- 
ployees. All 72 plans are from mines with United Mine 
Workers of America (UMWA) representation. Data on 
bonus plans from six nonunion mines have also been re- 
viewed. There are no differences in these mines from the 
72 UMWA mines; the structure of the bonus plans in 
union and nonunion mines appears quite similar. 

The sample of bonus plans was drawn by convenience. 
There is no national source of coal bonus plans. The major 
strategy in obtaining the plans was to use connections in 
the coal industry established through the Carnegie Mellon 
Coal Research Program. This research program has spon- 
sorship of 17 major coal producers in the United States. 
When these organizations joined this project (1981-82) 
they accounted for about 70 pet of the underground coal 
produced in the United States. Through these connections 
and others developed during the course of the project, the 
descriptions of implemented plans in 72 different mines 
were obtained. 

Are the data representative? There is reason to be- 
lieve they are. First, the sample of plans that will be re- 
ported come from a representative sample of companies 
under the BCOA-UMWA agreement. Second, the 
Carnegie-Mellon coal project team talked with a lot of 
managers and union officials over the last 5-yr period, and 
the bonus plans learned about through these discussions 
(but not included in this sample), seem similar in design to 
those that are reported in this paper. Third, the nonunion 
bonus plans reviewed by the project team are similar in 
form to those in the sample of the 72 mines. 

The basic position is that if bonus plans from all of the 
mines with plans were available, the modal characteriza- 
tion would not be different from the sample of 72 mines 
reported in this paper. 



The following 15 tables characterize the 72 plans 
along most of the decisions that were enumerated previ- 
ously. For example, plans were coded in terms of whether 
they paid out weekly or monthly, or whether they paid out 
with a single check or a separate bonus check. Coding of 
all of the 15 decisions was not done because of limitations 
on the descriptions of plans. 

Table 1 shows that most of the plans pay out on a 
monthly basis. The seven observations in the other cate- 
gory refer to six biweekly and one quarterly calculation 
period schemes. Table 2 shows the period in which the 
plans paid out a bonus versus the period for calculating a 
bonus. Most plans paid out on a monthly basis. Table 3 
shows that about half of the plans paid out by a separate 
check, the other half included the bonus payout in the 
regular check. 



Table 1. — Bonus calculation period 

Period 



pet 



Monthly 87.5 

Other (6 biweekly, 1 quarterly) 9.7 

Weekly 2.8 

Total 100.0 



Table 2. — Bonus payment period 

Period 



pet 



Monthly 90.3 

Other (6 biweekly, 1 quarterly) 9.7 

Total 100.0 



Table 3.— Form of payout 



pet 



Regular payroll check 51 .4 

Separate check 48.6 

Total 100.0 



108 



Table 4 indicates that 61 pet of the plans did not incor- 
porate safety as one of the elements of the bonus. Thirty- 
nine percent did use improvements in safety performance 
in calculating a bonus. Table 5 shows that absenteeism is 
related to the bonus payout scheme. Table 6 indicates that 
none of the plans used supply costs in determining bonus 
payments. 



Table 4.— Existence of safety bonus 



pet 



No 61.1 

Yes 38.9 

Total 100.0 



Table 9 shows that all the mines selected single versus 
multiple standards. 



Table 9. — Number of standards 



pet 



Single standard 100.0 

Multiple standard 

Total 100.0 

Table 10 looks only at the plans that incorporated 
safety performance in their bonus. For these plans, the 
majority include both lost-time accidents (LTA's) and vio- 
lations. The next set of plans with a safety component 
include only LTA's. 



Table 5. — Absenteeism connected to bonus 



Table 6. — Supply cost included in bonus plan 



Yes 
No . 



pet 



Yes, to production 87.5 

No 5.6 

Yes, to production and safety 5.6 

Yes, other 1 .4 

Total 100.0 



pet 

0.0 
100.0 



Table 7 shows that there is a high degree of unanimity 
about the form of production formula. Tons per week per 
workforce is compared to a standard tons per week per 
standard workforce. The appendix to this paper gives an 
example of specific production formula. Table 8 indicates 
that production standards were estimated from historical 
records versus estimated budgets. 



Table 7.— Production bonus formula 



pet 



Tons per week, adjusted 98.6 

Tons 1.4 

Total 100.0 



Table 10. — Basis of safety bonus 



pet 



Not applicable 61 .1 

LTA and violation incidences 25.0 

Violation incidence and severity 4.2 

LTA and violation incidences and severity 2.8 

LTA incidence and severity 2.8 

LTA incidence and severity and violation severity 1 .4 

LTA incidence and severity and violation incidence 1 .4 

LTA incidence 1 .4 

Total 1100.0 



LTA Lost time accident. 

1 Does not add to total shown owing to independent rounding. 

Table 11 examines the source of the safety bonus. The 
table indicates that the primary source is savings from 
fewer accidents and violations. 



Table 11.— Source of safety bonus 



pet 



Not applicable 62.5 

From safety gains 25.0 

From both production and safety 11.1 

From production gains 1 .4 

Total 100.0 

Table 12 focuses on plans that use production gains to 
reward safety performance. The table shows that in this 
case firms are more likely to use production gains for 
safety bonuses. 



Table 8.— Basis for production standard 



pet 



Historical 98.6 

Expected budget estimate 1 .4 

Total 100.0 



Table 12. — Distribution of production gains to safety 

pet 

25 pet safety, 75 pet production 1 .4 

50 pet safety, 50 pet production 13.9 

pet safety, 1 00 pet production 75.0 

Other 9.7 

Total 100.0 



109 



Table 13 indicates that money was the form of bonus 
payment. 

Table 14 shows that the majority of the plans paid out 
in a linear function. 

Table 15 presents a summary of the modal character- 
istics of bonus plans in the coal industry. 



Table 13.— Bonus component 



Table 14. — Production bonus rate function 



pet 



Only monthly payments 98.6 

Other ]A 

Total 100.0 



pet 



Linear function 97.2 

Accelerated function 2.8 

Total 100.0 



Table 15. — Modal characterization of bonus plan 

Bonus calculation period Monthly. 

Bonus payout period Do. 

Form of bonus payout Separate check or part of pay- 
roll check. 
Base of bonus: 

Production Yes. 

Safety Yes. 

Absenteeism Yes. 

Supply costs No. 

Production formula Weekly tons per workforce. 

Compares to standard tons 
per standard workforce. 

Selection standard Historical records. 

Number of standards Single. 

Bases of safety formula Accidents and violations. 

Selection of standard Historical records. 

Source of funds — safety Production and safety bonus. 

Distribution: 

To company No data. 1 

To management and employees Do. 1 

Types of payment Money. 

Payoff schedule Linear. 

Unit of payout The mine. 

Organizational arrangements No data. 1 

1 No information in the description of the plans to permit coding. 



ANALYSIS OF BONUS PLANS— THEORETICAL 



In this section the bonus plans are analyzed in terms 
of their effectiveness. The tools for this analysis come from 
motivational theory. That is, the strengths and weak- 
nesses of modal bonus plans will be analyzed utilizing 
motivational theory. The plan that is characterized in 
table 15 represents a profile of choices. That structure 
versus alternative structures has different implications. 
The theory can provide information about the conse- 
quences of that plan. 



WHAT DOES EFFECTIVENESS MEAN? 

Bonus plans are instituted for a variety of reasons. 
Some plans are designed to increase retention and to re- 
duce absenteeism and tardiness. Other plans directly focus 
on increasing productivity or costs. Still other companies 
introduce various incentives because they are changing 
the form of the organization, and they want the incentive 
plan to be congruent with this new managerial philoso- 
phy. In this case, the change in management philosophy 
and culture drives the introduction of the new pay system. 

From analysis of the bonus plans and from visits to 
companies with plans, it seems that improvements in pro- 
ductivity and costs are the primary reasons for initiating 
bonus plans in underground coal mining. The basic as- 
sumption is that the plan will increase motivation, which 
should in turn lead to improvements in performance and 
costs. The question posed is to what extent is the bonus 
plan likely to increase motivation and performance. To the 
extent that the plan can increase motivation and perform- 
ance it will be effective. 



THEORETICAL ANALYSIS 

If the assumption is that a bonus plan will increase 
motivation and then performance, the analysis initially 
needs to examine how the structure of properties of the 
plan affects motivation. 

The analysis will focus primarily on the link between 
the plan and motivation. The reader, of course, can see 
that increase in motivation might not lead to high per- 
formance. A group of employees could be highly moti- 
vated, but ability, organizational, or environmental fac- 
tors may preclude improvements in performance. 

What are the conditions that would lead to high motiva- 
tion? What does it mean to say a bonus plan can lead to 
high levels of motivation? A condition of high motivation 
can be characterized in terms of four factors or questions. 

1. To what extent do the workers think they are capable 
of performing at higher levels of performance? 

2. To what extent do workers think that improving 
their performance is linked to rewards? 

3. To what extent do workers think that increased per- 
formance will lead to punishments? 

4. To what extent are the rewards (punishments) from 
the bonus plan perceived as valuable (harmful) to the 
workers? 

The first question simply asks whether workers per- 
ceive (subjective) they can improve their performance. 
There could be environmental factors (e.g., bad roof) that 
could preclude workers from being optimistic about in- 
creasing performance. The second question simply asks 
whether improvements in performance are closely tied to 
bonus payments. More performance leads to more bonus 



110 



payments. The third question acknowledges that negative 
rewards can be attached to any bonus plan. For example, 
if a crew is opposed to the bonus plan they can exert 
penalties on workers for participating in the plan. The last 
question indicates that workers differentially prefer cer- 
tain rewards to others. Money is not equally valued by all 
coal miners. Unless the rewards are valued they will not 
be motivating. 

High motivation then means — 

Workers believe they can improve performance levels. 

High performance is associated with higher rewards. 

Rewards are considered valuable. 

Only minimal negative rewards are associated with in- 
creasing performance. 

Table 15 summarizes the structure of the modal bonus 
plan. How does this plan affect the four questions enumer- 
ated previously? In this analysis some structural factors 
will be more important than others. Also, in many cases 
the analysis will be on relative impacts of this modal plan 
on the four questions. 

1. Bonus calculation period. — The calculation period 
can affect the motivational levels. Specifically, the shorter 
the time period the closer the workers will see links be- 
tween their increased levels of performance and the bonus, 
and hence, the greater levels of motivation. The shorter 
time period provides quicker knowledge of bonus pay- 
ments and avoids negative cumulative effects. This refers 
to a situation where a miner has difficulty (e.g., bad condi- 
tions) meeting the quota early in a period and gives up 
later in that period thinking he or she is unlikely to meet 
the quota. The longer the period, the more likely this can 
happen. Basically this analysis would indicate that 
weekly calculation periods would be better than monthly, 
and monthly would be better than quarterly. 

2. Bonus payout periods. — This dimension is less im- 
portant because knowing that a bonus was earned is prob- 
ably more important than knowing it was paid. 

3. Inclusion of safety. — Inclusion of safety formally in 
the plan has important motivational consequences. A 
dominant concern for most miners in this study was that 
bonus plans could increase accidents. If accidents formally 
are part of the plan, then it is less likely they will be 
negative consequences (question 3). 

4. Inclusion of absenteeism. — Most bonus plans pay 
out on days worked. So if one works fewer days one gets 
less bonus payments. There is nothing in this feature that 
increases motivation to work harder. However, if workers 
receive the same bonus regardless of attendance, conflicts 
would result and the plan would not work. 

5. Inclusion of supply costs. — This feature does not 
affect the motivational impact of a bonus plan. 

6. Selection of the formula. — Most of the plans in this 
study have a fairly simple formula of comparing actual 
production per workforce to a standard. Simple formulas 
are important because they facilitate understanding and 
strengthen the perception about the link between expected 
performance and bonus payments. 



7. Selection of the standard. — This is critical because 
it will affect question 1 — to what extent are workers capa- 
ble of performing at a higher level of performance? If the 
standard is too high, workers will not respond to question 
1 positively and no increased motivation will occur. 

8. Single versus multiple standards. — A problem 
with the existing plans is that they only use one standard. 
The problem is that mining conditions vary. So if workers 
go through a long period of bad conditions, they will not 
think they are capable of meeting performance standards 
and motivational levels will drop off. 

9. The safety formula in most plans is based upon 
lost-time accident frequency, severity, and violations. — The 
important issue is whether workers have control over acci- 
dent frequency, severity, and violations. To the extent that 
an inspector, for example, simply writes more violations in 
one section than another or in one mine versus another, 
would lower the workers' perceptions that they are capa- 
ble of reducing violations. The issue is not whether safety 
indexes should be included, but whether they are control- 
lable. Low perceived control means low motivation. 

10. Selection of safety standards. — The argument is 
the same as with production. The standards must be per- 
ceived as obtainable by the workers (not simply by man- 
agement) for motivation to occur. 

11. Source of safety bonus. — Most plans that paid out 
on safety used production gains as a source of the safety 
payout. This is a desirable motivational strategy, because 
in many of the mines visited it was difficult to generate 
regular major savings from accident reduction. Therefore, 
by using some gains from production, the safety reward 
would be larger and more valuable (question 4). 

1 2 . Types of payment. — All of the bonus systems used 
money as a form of payment. However, in our national 
study of coal miners 2 there is some evidence that money 
may not be the major motivator and time off may be impor- 
tant. The point is that the plan's effectiveness is based on 
whether the provided reward is considered valuable. 

13. Payoff schedule. — The modal bonus plan used a 
linear versus an accelerated schedule. An accelerated 
schedule has stronger motivational impacts at higher lev- 
els of performance. If workers feel they are capable of 
performing at higher levels of performance (question 1), 
then accelerated schedules should strengthen the connec- 
tion between higher levels of performance and higher lev- 
els of motivation (question 2). 

14. Unit of payout. — All of these plans pay out at the 
mine level (versus crew). The critical factor then becomes 
the size of the mine. The larger the mine, the less likely 
workers will perceive there will be a connection between 
meeting the standard and receiving a payoff and hence, 
the lower the motivation. 



2 Goodman, P. S. Feedback on Employee Attitudes in the Coal Industry. 
Unpublished working paper, 1986; available upon request from P. S. Good- 



Ill 



15. Organizational-technical arrangements. — While 
there is nothing in the description of the 72 plans to indi- 
cate whether there are complementary organizational ar- 
rangements, experience in the coal industry over the last 
10 yr indicates there are no organizational arrangements 
in the modal bonus plans. The problem is there is no fea- 
ture in the design of the plan to indicate what activities 
will result in greater productivity. Working harder, coor- 
dinating better within and between sections, making sug- 
gestions, improving the management of delays, improving 
the management of supplies, and reducing absenteeism 
can all increase productivity. However, typically the 
modal plan does not explicitly focus on any of these critical 
instrumental behaviors. In addition to focusing on these 
behaviors there needs to be some mechanism to insure 
these behaviors get done. That is, there needs to be support 
activities built into and plan to identify, support, and en- 
courage such behaviors. Such support mechanisms in- 
clude, but are not limited to, diagnosis of organizational 
and technical problems prior to introducing the plan, 
training, formal suggestion systems, and formal review 
and followup procedures. Some successful bonus systems 
used in other industries include such support mechanisms 
as part of the plan. 

Table 16 summarizes the relationship between the 
features of the modal bonus plan and increasing motiva- 
tion. 

A review of the modal plan shows that the following 
factors detract from the plan's motivation potential. 

Monthly calculation time. 

Single standard. 

Safety formula. 

Reliance on pay. 

Mine unit of payout. 

No organizational arrangements. 
The following factors enhance the motivation poten- 
tial. 

Inclusion of safety. 

Inclusion of absenteeism. 

Weekly tons per workforce formula. 

Source of safety bonus. 



Table 16.— Modal plan features and motivation 



Feature 



Consequence 



1 . Monthly calculation time Reduces motivations 

(questions 1 and 2). 

2. Monthly payout time No effect. 

3. Inclusion of safety Increases trust and mini- 

mizes a negative conse- 
quence (accidents) 
(question 3). 

4. Inclusion of absenteeism Maintains equity. 

5. Exclusion of supply costs No effect. 

6. Weekly tons per workforce formula Simple, facilitates under- 

standing (question 1 and 
2). 

7. Selection of standard No direct impacts, de- 

pends on level at mine 

8. Single versus multiple standard Single standard will de- 

crease individuals' be- 
liefs that they are capa- 
ble of meeting expected 
standards (question 1). 

9. Safety formula To the extent that some 

of the indicators such as 
severity or number of vi- 
olations are outside the 
control of the worker, the 
motivation will be de- 
creased (question 1). 

10. Selection of safety standard See feature 7. 

1 1 . Source of safety bonus Inclusion of bonus re- 

wards from production 
gains increases the 
amount and hence value 
of the reward (ques- 
tion 4). 

12. Reliance only on pay Reduces the reward value 

of the incentive (ques- 
tion 4). 

13. Linear pay at schedule No main effect on motiva- 

tion, slight preference for 
accelerated schedule 
(question 1). 

14. Mine unit of payout In large mines, motiva- 

tional potential will be re- 
duced (question 2). 

1 5. No organizational arrangements Reduces motivational and 

performance potential. 



ANALYSIS OF BONUS PLANS— LITERATURE 



Another way to analyze the modal incentive plan is to 
examine the research about incentive plans. Empirical 
findings in the research literature might help assess the 
effectiveness of the modal bonus plan in the coal industry. 
While the literature on incentive plans is not extensive, 
there are some "stylized facts" that might aid in assessing 
bonus plans in the coal industry. The type of findings can 
be divided into two general categories. The first type of 
findings deal with the inherent characteristics of the 
bonus plan. The second set of findings deal with organiza- 
tional factors that contribute to successful bonus plans. 



FINDINGS ON INHERENT PLAN 
CHARACTERISTICS 



1. Unit of payout. — Table 17 provides an analysis by 
Lawler 3 based on findings in the research literature, about 
the consequences of different units of payout. The table 
presents ratings for individual groups and organizational 
level bonus plans. The mining plan would be characterized 
as a productivity based bonus at the organizational (mine) 
level. The basic findings are that organizational plans are 
average in tying pay to performance, have low negative 
side effects, are average in encouraging cooperation, and 
above average in getting accepted. The table also shows 
that plans based on productivity are stronger than those 
based on costs or profitability. The mine plans are based on 
productivity. If one compares across different types of 
plans, the organizational level plan is less powerful in 
tying pay to performance as compared with the group or 



The following research findings can help assess the 
effectiveness of the modal bonus plan in the coal industry. 



3 Lawler, E. E. Pay and Organization Development. Addison Wesley, 
1981, 253 pp. 



112 



Table 17. — Ratings of various bonus incentive plans 1 



Plan level 


Tie pay to 
performance 


Negative 
effects 


Cooperation 


Acceptance 


Individual: 

Productivity 

Cost effectiveness .... 

Superior's rating 

Group: 

Productivity 

Cost effectiveness .... 

Superior's rating 

Organizational: 

Productivity 

Cost effectiveness 

Profit 


5 
4 
4 

4 
3 
3 

3 
3 
2 


3 
2 
2 

1 
1 

1 

1 

1 

NR 


1 

1 
1 

3 
3 
3 

3 

3 

NR 


2 
2 
2 

3 
3 
3 

4 

4 

NR 



NR Not rated. 
'Low (1) to high (5). 



individual plan. This means that the plan will have less 
motivational qualities. 

The most obvious unit of analysis in coal mining is the 
group or crew and/or section. Coal is produced by a group, 
not by individuals. In that sense, an incentive at the group 
or section level appears to be more appropriate. Because 
crews or sections in coal mines are independent production 
units, bonuses at the crew level would not lead to competi- 
tion between groups. 

2. Attractiveness of rewards. — The research on the 
attractiveness of rewards has one clear finding: that there 
are important individual differences in the perceived at- 
tractiveness of pay. 4 While it is not clear what are all the 
predictors of people's preference, there are clear variations 
in the value people attribute to extra units of money. 
Given this finding, any program that is based solely on 
money will have less motivational potential than a pro- 
gram that individualizes rewards; that is, a program that 
lets people select rewards that are most valuable to them. 
In addition, there are data from this study that indicate 
that other factors (time off), in addition to pay, may be 
important motivators for miners. 

3. Timing of rewards. — In general, the longer the 
time period between the performance of desired behavior 
and the receipt of the reward, the less effective the motiva- 
tion potential of the bonus plan. 5 The shorter the period 
reinforces the facts that performance levels can be ob- 
tained and that the rewards are closely tied to perform- 
ance levels. As mentioned earlier, mine bonus plans pay 
off in a month, which is a relatively long period between 
initial performance and payoff. 

4. Controllable output. — Another critical finding is 
that the workers must perceive they can control the per- 
formance behavior that is being rewarded. 6 Factors that 
affect the perception of control include personality charac- 
teristics, physical environment, and equipment reliabil- 
ity. Bonus plans in this study do not reflect the environ- 
mental and technological factors that affect coal output 
that are not indicated in the plan. For example, a long run 
of bad conditions or difficulties with equipment outside the 
mining section, would reduce coal production and prevent 
the attainment of the production standard. When these 
exogenous factors affect coal production, they weaken the 
effectiveness of the plan. There is nothing in any of the 
plans to compensate for these exogenous shocks. 



4 Work cited in footnote 3. 
5 Work cited in footnote 3. 
sWork cited in footnote 3. 



FINDINGS ON FACTORS THAT AFFECT 
SUCCESSFUL BONUS PLANS 

Table 18 is a summary of factors indicating conditions 
that facilitate the functioning of incentive plans. 7 

Table 18.— Conditions favoring gainsharing plans 

Organizational characteristic Favorable conditions 

Size Small unit, usually less than 500 em- 
ployees. 

Age Old enough so that learning curve is flat- 
tened and standards can be set based on 
performance history. 

Financial measures Simple, with a good history. 

Market for output Good, can absorb additional production. 

Production costs Controllable by employees. 

Organizational climate Open, high level of trust. 

Style of management Participative. 

Union status No union, or one that is favorable to coop- 
erative effort. 

Overtime history Limited to no use of overtime in past. 

Seasonal nature of business . . Relatively stable across time. 

Workfloor interdependence . . . High to moderate independence. 

Capital investment plans Little investment planned. 

Product stability Few product changes. 

Comptroller-chief financial Trusted, able to explain financial mea- 

officer. sures. 

Communication policy Open, willing to share financial results. 

Plant manager Trusted, committed to plan, able to articu- 
late goals and ideals of plan. 

Management Technically competent, supportive of par- 
ticipative management style, good com- 
munication skills, able to deal with sug- 
gestions and new ideas. 

Corporate position (if part of Favorable to plan, 
large organization. 

Workforce Technically knowledgeable, interested in 

participation and higher pay, financially 
knowledgeable or interested. 

Plant support services Maintenance and engineering groups com- 
petent, willing to respond to increasing 
demands. 

The table can be interpreted two ways. First, coal 
mines that have the favorable conditions will have more 
successful bonus plans. That means smaller mines that 
are nonunion and have good maintenance groups will 
have more successful bonus plans. Another way to use the 
list is to ask whether the organization and technology of 
coal mining is congruent with introducing bonus plans; 
that is, there is a lot of similarity in mining coal across all 
the companies in the study. Is there anything in this proc- 
ess that would facilitate or not facilitate the introduction 
of a bonus plan? 

Table 18 lists a number of favorable conditions unique 
to coal mining. 

Financial measures of productivity are fairly straight- 
forward. 

Business is generally not seasonal. 

There have not been major capital and technological 
innovations in the past 6 yr. 

Product is stable. 
On the other hand, there are a number of conditions 
that are not favorable to bonus plans. These observations 
come from an analysis of 25 mines of the 17 largest produc- 
ers in underground coal in the Carnegie Mellon coal proj- 
ect. 

The climate in many mines is not very open. 

The style of management is traditional. 



'Work cited in footnote 3. 



113 



Union-management relations are not highly coopera- 
tive. 

Communication policy is typically not open to share fi- 
nancial information. 

Management is typically not highly supportive of partic- 
ipation, asking suggestions, or the bonus plan itself. 

Both lists identify factors that facilitate and inhibit 
the successful utilization of bonus plans in the coal indus- 
try. 

The basic conclusion that can be drawn from this anal- 
ysis of the literature is that bonus plans in the coal indus- 



try would be more powerful in motivating performance to 
the extent to which — 

The bonus is organized at the crew or section level ver- 
sus the mine. 

The bonus is in a form (money or time off) valued by the 
worker. 

The bonus calculation period is weekly. 

The bonus adjusts for uncontrollable events. 

The more a given mine can enhance the favorable condi- 
tions (table 18), the greater the success of the bonus plan. 



ANALYSIS BONUS— MINERS' VIEWS ON BONUS PLANS 



In this section, the structure of bonus plans is re- 
viewed by examining miners' views of incentives. Data 
come from interviews done from a contract with the Bu- 
reau of Mines on "Research To Determine the Feasibility 
of Utilizing Employee Assistance Programs for the Mining 
Industry."® This information was collected at four UMWA 
mines with incentive plans. Table 19 shows the basic char- 
acteristics of the mines. 



Table 20. — Bonus payout period, percent 



Monthly 

Biweekly 

Other 

NA Not available. 



Mine 1 



NA 
NA 
NA 



Mine 2 



61 

39 





Mine 3 



49 

46 

5 



Mine 4 



63 
28 
10 



Table 19. — Mine characteristics 



Mine 


Size 


Location 


Technology 


1 


<400 
<300 
<300 
<300 


Virginia 

West Virginia 

do 

do 


Continuous. 


2 

3 

4 


Do. 
Do. 
Do. 



Table 21 . — Basis for bonus, yes respondents, percent 





Mine 1 


Mine 2 


Mine 3 


Mine 4 


Production 

Accidents 

Absenteeism 

Supply costs 


100 

100 

100 

72 


98 
86 
85 
40 


97 
70 
70 
42 


83 
90 
73 
59 



The mines belong to different major coal companies. 
While these four are clearly large relative to the average 
coal mines in the United States, they were similar to other 
mines in the sample in terms of organizational structure, 
technology, personnel, and so on. They are representative 
of large mines in the United States. These four mines were 
selected because they were the only incentive mines in the 
initial sample of 25 mines. 

The bonus plans in each of the mines match the modal 
plan (table 15). None of the four companies had paid out 
more than two bonuses over the last year. 

PERCEPTIONS OF BONUS PLANS 

Two types of data are examined. The first type of data 
concern miners' views about design or structure of incen- 
tive plans. The second set of data concern the motivational 
potential of the plan in their respective mine. 

Table 20 shows that miners preferred to receive 
monthly bonus payouts. Unfortunately no questions were 
asked about the preferred bonus calculation period. Min- 
ers were then asked what should be included as the basis 
of a bonus plan. As table 21 indicates, the majority felt 
that production, accidents, and absenteeism should be in- 
cluded in the plan. There was less consensus on including 
supply costs. 



8 Goodman, P. S. Research To Determine the Feasibility of Utilizing Em- 
ployee Assistance Programs for the Mining Industry — Final Report (con- 
tract J0100069, Carnegie-Mellon Univ.). BuMines OFR 73-86, 1986, 234 
pp.; NTIS PB 86-227089. 



The formula in all four mines was in the weekly tons 
per workforce format. Earlier it was argued this was a 
relatively simple format and should be easily understood. 
Table 22 shows that most miners report that they have at 
least some understanding of the formula and operations of 
the plan. It is interesting to note that less than half the 
miners have a good or very good understanding of the 
plan. In mine 4, miners across the board express less 
understanding of the plan. 

Table 22. — Understanding the bonus plan, percent 





Mine 1 


Mine 2 


Mine 3 


Mine 4 


Very good 


NA 
NA 
NA 
NA 
NA 


12 
29 
32 
17 
10 


9 
39 
30 

9 
13 


5 


Good 

Some 

A little 


12 
34 
32 


None 


17 



The standard production quota really determines if a 
bonus will be paid. In table 23 miners were asked whether 
they thought the standard was too high. In mines 2 and 3, 
the majority said the standard was about right. In mine 4, 
the reverse was true. 

In table 24 data are presented on what types of indi- 
viduals should be included in the plan. Respondents seem 
to prefer a plan that includes UMWA-underground, 
UMWA-surface, and supervisors. The majority, but to a 
less degree, feel other production managers, salaried 



114 



safety, engineering, and trainee personnel should be in- 
cluded. There is less consensus on whether mine clerks 
and other clerical people should be included. 

Tabic 23. — Standard for production, percent 



Too high 

About right 

Too low 

NA Not available. 



Mine 1 



NA 
NA 
NA 



Mine 2 Mine 3 



23 

77 




24 
64 
12 



Mine 4 



73 

24 

3 



Table 24. — Who should be included in plan, 
yes respondents, percent 





Mine 1 


Mine 2 


Mine 3 


Mine 4 


UMWA: 

Underground 

Surface 

Supervisors 


NA 
NA 
NA 
NA 
NA 
NA 


100 
87 
98 
64 
73 
45 


100 
94 
91 
81 
78 
62 


100 

100 

66 


Other production managers 
Engineers, safety training . . 
Mine clerks 


61 
61 
59 



Miners were also asked whether there should be a 
separate bonus program for management. Table 25 indi- 
cates that most miners felt that there should not be a 
separate program. 



Table 25. — Have separate plan for management, percent 





Mine 1 


Mine 2 


Mine 3 


Mine 4 


Yes 

No 


100 



37 
63 


13 
87 


50 
50 



Table 26 indicates the type of bonus payment miners 
would prefer to receive. While there is some variation 
across the mines, two things can be concluded: (1) Cash is 
not the only preferred payment, and (2) some combination 
of cash and time off would be a more preferred payment. 

Table 26. — Type of payment, percent 



Cash only 

Time off only .... 

Fringe only 

Cash and fringe . . 
Cash and time off 
Other 



Mine 1 



15 
12 

9 
42 
22 



Mine 2 Mine 3 



34 

5 



20 

34 

7 



24 

6 

9 

12 

33 

6 



Mine 4 



15 
10 
5 
17 
32 
21 



In an earlier discussion, it was pointed out that there 
were no formal mechanisms in the modal bonus plan to 
direct workers' attention on the critical strategies for in- 
creasing productivity. The underlying assumption seemed 
to be work harder rather than work smarter. There is 
nothing to assist in coordination, planning, or eliciting 
new productivity ideas. 

To explore the informal functioning of the mines, min- 
ers were asked three questions. First, "how often do they 



talk to their boss about mining activities?" The basic re- 
sults in table 27 indicate that the majority talk about 
mining activities at least once a week. The second question 
was "who was interested in their ideas for improving 
work?" At least one-half said no one, the next most inter- 
ested party was the other miners (see table 28). 



Table 27. — How frequently boss talks 
about mining activities, percent 





Mine 1 


Mine 2 


Mine 3 


Mine 4 


Once a day 

Once a week 

Once a month 

Several times a year 

Never asked 


24 
22 
5 
20 
29 


31 

41 

5 

5 

18 


27 

40 

3 

3 

27 


24 
22 
5 
20 
29 







Table 28. — Who is interested in your suggestions 
and opinions, percent 





Mine 1 


Mine 2 


Mine 3 


Mine 4 


No one 

Superintendent . 


59 
5 
5 

30 
1 


56 
2 
17 
12 
13 


53 

7 

3 

27 

10 


59 
5 


Mine foreman 


5 


Other miners 

Other 


29 
2 



The third question asked them to generate some pro- 
ductivity improvement suggestions (table 29); at least 50 
pet had no suggestions to make. The point is that bonus 
plans really work if people work harder and smarter. 
These questions indicate that mechanisms are not in place 
to let miners work smarter in order to generate new ways 
to increase productivity at work. 



Table 29. — What suggestions could you make to improve 
productivity at this mine, percent 





Mine 1 


Mine 2 


Mine 3 


Mine 4 


No suggestions 

Maintenance improvement . . 
Mining techniques-plans . . . 
Other 


NA 
NA 
NA 
NA 


76 

10 

5 

9 


54 
18 
11 
17 


80 
5 
3 

12 



NA Not available. 

What can be learned from these findings? In general, 
many aspects of the modal plan in coal mining is consis- 
tent with how miners would like to see the plan designed. 
However, there are some differences. First, the modal plan 
relies on cash as an incentive. The data indicate that min- 
ers want cash plus other incentives (e.g., time off). Second, 
there are some differences in who should be included in a 
plan. Third, and this is not a difference, the understanding 
of the plan seemed lower than had been predicted given 
the rather simple nature of the formula. Another point is 
that whether the standards are appropriate depends on 
the individual mines. In mine 1, where bonuses have not 
been paid, respondents feel the standard is too high. The 
last point is that neither the bonus plans in these mines, 
nor the organization of the mines, are designed to facili- 
tate productivity-related suggestions that might improve 
the chances of making a bonus. 



115 



A series of questions were asked to determine the 
motivating potential of the existing plan. Remember that 
earlier in this paper it was stated that a plan would be 
motivating to the extent that it led miners to believe — 
They were capable of producing more, and 
They would receive more if they produced more. 
Table 30 indicates whether miners feel they can in- 
crease the level of their performance. At least 50 pet felt it 
was unlikely they could increase their performance over 
current levels. Less than 20 pet felt it was likely they could 
increase their performance. 

Table 30.— Likelihood of producing more coal, percent 





Mine 1 


Mine 2 


Mine 3 


Mine 4 


Not at all 


NA 

NA 
NA 
NA 
NA 


37 
34 
13 
13 
3 


17 
31 
24 
14 
14 


46 


Only a little 

Somewhat 

Quite likely 


22 

22 

8 


Extremely 


2 



Table 31 asks a similar question but focuses on down- 
time, a major cause of lost production. More than 60 pet 
felt it is very unlikely they would be able to reduce down- 
time. 

Table 31. — Likelihood of reducing downtime, percent 



Not at all . . 
Only a little 
Somewhat 
Quite likely 
Extremely . 



Mine 1 



35 

38 

8 

4 

5 



Mine 2 Mine 3 



53 
24 
11 
12 




31 
31 
31 

7 




Mine 4 



43 

27 

22 

8 





Table 32 asks a different question. Basically it asks if 
a person did improve his or her performance, would the 
mine earn a bonus. The data say that a majority of the 
respondents did not think bonuses would be earned. 



Table 32. — Likelihood of receiving 
an incentive bonus, percent 



Not at all . . 
Only a little 
Somewhat 
Quite likely 
Extremely . 



Mine 1 



57 

30 

11 







Mine 2 



44 
16 
19 
16 
6 



Mine 3 



57 

27 

13 



3 



Mine 4 



73 

20 

5 

2 





If miners feel they can not improve their performance 
and they do not think bonuses will be forthcoming, the 
bonus plan has low motivation potential. One reason min- 
ers may be pessimistic about the plan is because it benefits 
only management and/or it is administered unfairly. Ta- 
bles 33 and 34 show that miners feel the plan benefits both 
the miners and the company. In mines 1 and 4, respond- 
ents report that the program is administered fairly. 



Table 33. — Who benefits from the program, percent 




Mine 1 


Mine 2 


Mine 3 


Mine 4 


Primarily — 
The mine 


NA 
NA 
NA 


3 
17 
80 


7 
22 
71 


2 


The company 

Both 


53 
45 



NA Not available. 



Table 34. — Administration of plan, percent 



Very fairly 

Fairly 

Not fairly . 



Mine 1 




37 
63 



Mine 2 



5 
87 



Mine 3 



10 
67 
23 



Mine 4 




35 
65 



The basic finding from these results is that in these 
four mines the bonus plan does not elicit high motivation 
potential. 



DISCUSSION 



A theoretical, literature, and empirical analysis of the 
structure of bonus plans in underground coal mining has 
been provided. There are two basic conclusions from the 
analysis. First, the inherent structure of the bonus plan is 
not conducive to increase motivation potential and per- 
formance. 

Plans that — 
Pay out at the organizational mine level (versus group), 
Pay out only in money (versus other rewards), 
Use single standards (versus adjusting for noncontrol- 
lable events, e.g., physical conditions), 
Are calculated on a monthly basis, and 
Provide no organizational arrangements to increase pro- 
ductivity, are not powerful in increasing the motivational 
or performance potential. Granted there are some positive 
structural features such as the inclusion of safety and a 
simple formula, but these do not offset the negative im- 
pacts of the features listed. Some mines can have more 



success with these types of plans than others. These mines 
would have — 

To be small mines with less than 200 employees; 

To have a good market that could absorb additional pro- 
duction; 

To have good historical production data; 

To have relatively stable production conditions; 

To have a climate with high degrees of trust; 

To have a participative management style; 

To have cooperation between union and management; 

To have no major capital investment plans; 

To have a willingness to share production information; 

To have mine superintendents committed to making the 
bonus plan work; and 

To have good support services — maintenance. 
This issue is not whether a mine has some of these at- 
tributes. All are necessary to make a plan work. 



116 



APPENDIX.— PRODUCTION BONUS FORMULAS— MINE X 



Bonus = (Number of production shifts worked by individ- 
ual) x Change in tons per month + change in 
tons per roster person-day) x (bonus payment), 

Where Change actual tons per month 

in tons - standard tons per month 

per month standard tons per month 



Q/Q, 



and Change in tons per roster person days = P - 

Where P = actual tons per month/actual roster person- 
days per month 
and Q = standard tons per month/standard roster 
person-days per month 



actual tonage per month 
Let X = -target tonnage per month x 

target tons per month * ' 

actual tons per person-day 
Y _ - target tons per person-day x 10Q . 
target tons per person-day " ' 

and Z = regular scheduled production days worked. 

Production bonus = (bonus payment) x (X + Y) x (Z). 



117 



BASIC GUIDELINES FOR ESTABLISHING AN EMPLOYEE 

ASSISTANCE PROGRAM 



By Nancy D. Campbell 1 



ABSTRACT 



This paper discusses the concepts and processes important to the development and 
implementation of an employee assistance program (EAP). Program planning strate- 
gies and marketing tools are reviewed, as are suggestions for training, casefinding, 
program maintenance, and program evaluation. 



INTRODUCTION 



From their earliest beginnings in the 1940's and 
1950's, employee assistance programs have come to repre- 
sent one method for dealing with troubled employees 
whose performance on the job is being affected by outside- 
of-job factors. The purpose of this paper is to examine the 
EAP concept and to describe its design, development, im- 
plementation, and evaluation. Because the components 
necessary for the establishment of a successful EAP are 
similar regardless of the industry involved, such processes 



will be discussed generically. Those desiring specific infor- 
mation on the feasibility and application of EAP's to the 
mining industry are referred to an earlier report (1 ). 2 That 
report established that EAP's are appropriate and valu- 
able when the decision to establish an EAP has been based 
upon the needs of a specific worksite. This paper will ad- 
dress those processes involved in establishing a viable pro- 
gram. In order to do so, it is important to define the EAP 
concept and to briefly introduce common issues of use. 



THE EAP CONCEPT 



An EAP is a structured approach for assisting em- 
ployees with those off-the-job problems that can affect job 
performance. While EAP's were initially designed to iden- 
tify and help those employees with alcohol problems, the 
EAP's of today generally take a much broader perspective. 
In addition to alcohol and drug abuse, a myriad of other 
problems — marital-family, physical, financial, legal, and 
vocational — can negatively influence job performance. 
Most often a combination of such problems are present. 
Thus, the role of the EAP system has expanded in the past 
two or three decades and reflects the growing concern for 
achieving and maintaining an emotionally healthy work- 
force. 

While EAP's come in a variety of forms, they typically 
involve self-referral or referral by a supervisor or union 
representative for an off-the-job problem. The EAP coordi- 
nator evaluates the problem and refers the individual and/ 



or family to the appropriate treatment agent in the com- 
munity. The diagnostic sessions are usually covered by the 
organization's insurance program, while ongoing treat- 
ment services may or may not be so covered. Most EAP's 
operate off site, utilizing professionals on contract, while 
some may elect to develop in-house programs utilizing 
professionals who are on staff. Such design decisions will 
be discussed more thoroughly in the sections to come. 

In general, the overall goal of an EAP is to restore the 
employee to normal work behavior and productivity and/ 
or prevent work performance problems due to personal 
concerns. The power of this approach rests both with early 
identification and with the motivating elements inherent 
to employment. People want to keep their jobs, and the 
possibility of losing one's employment is a strong motiva- 
tional force in getting the troubled employee to seek help. 



Psychologist, Hamilton Center, Terre Haute, IN. 



2 Italic numbers in parentheses refer to items in the list of references at 
the end of this paper. 



118 



ESTABLISHING AN EAP 



The purpose of this section is to describe in more detail 
the specific developments needed to establish a viable 
EAP system. As with any proposed program or service, 
careful planning and thorough attention to the implemen- 
tation of that plan are essential to program success. At a 
minimum, such a plan should include (1) identification of 
need, (2) joint labor-management planning, (3) program 
design, (4) orientation and training of management, su- 
pervisors, and employees, (5) program maintenance, and 
(6) program evaluation. Each component will be discussed 
in more detail in the sections to come. 



NEED IDENTIFICATION 

Prior to establishing an EAP, an organization must 
recognize that it has a need for such services and demon- 
strate a commitment to identifying strategies for address- 
ing this need. The initial interest in establishing a pro- 
gram may be generated by a specific segment of the 
workforce, but ultimately there can be no program with- 
out the full cooperation and support of key personnel at all 
levels. Any number of events might precipitate serious 
discussions — an increase in accidents, absenteeism, an at- 
tempted suicide, labor-management contract negotiations, 
an emerging awareness of health and wellness issues by 
top-level management. 

In general, management-initiated discussions repre- 
sent the most common starting point and must clarify 
early on who has the authority to make programming 
decisions. In those companies where authority is decen- 
tralized, the manager at each site can set policy without 
obtaining corporate approval. In other more centralized 
organizations, home-office approval is required before any 
change in existing policy can be initiated (2 ). 

Once determination of authority has been examined, 
clarification of the scope of the problem can be pursued. 
Involvement of both labor and management becomes cru- 
cial in assessing the prevalence and incidence of factors 
potentially affecting job performance and in establishing a 
rationale for pursuing an EAP. Frequently, an outside 
consultant knowledgeable about EAP's is brought in to 
facilitate the process, and it is usually wise to initially 
stage separate discussions with labor and management to 
encourage freedom of expression. If both sides unilaterally 
decide that an EAP is justified, then the stage is set for a 
joint labor-management dialogue. 



LABOR-MANAGEMENT DIALOGUE 

The purposes of the labor-management dialogue are 

(1) to encourage cooperation and support for the program, 

(2) to jointly assess those elements within the work setting 
likely to impact successful development of a program, and 

(3) to establish a joint labor-management planning com- 
mittee responsible for the creation of policy and the setting 
of goals, the overseeing of program development and im- 
plementation, and the identification of marketing strate- 
gies (3 ). Each of these activities will be discussed in the 
following sections. 



The Involvement of Key Individuals 

The support of key individuals at all levels of labor 
and management is essential, as is the identification of 
those gatekeepers who are unlikely to support the efforts. 
Because an EAP must operate within the existing network 
of organizational relationship, it is imperative to know the 
lay of the land, the vested interests, the social politics, and 
the formal and informal lines of authority and power. The 
involvement of both formal and informal leaders works to 
establish a system of endorsement and trust that is invalu- 
able, and that will more likely lead to substantial future 
labor-management referrals. It is also suggested that a 
representative of the existing medical staff be included at 
the inception. This is to ensure that the EAP will not be 
regarded as a threat to current medical services and will 
be utilized as an option by medical practitioners at the 
worksites. Personnel and training departments should 
also be included. 

These key individuals form an ad hoc committee re- 
sponsible for selecting a permanent EAP planning com- 
mittee and for identifying its goals and objectives. Ideally, 
planning committee members will be chosen with these 
goals in mind and will be made clearly aware of the com- 
mittee's purposes before they are selected. 

Planning Committee 

The major purposes of a labor-management planning 
committee are to establish EAP goals and objectives, de- 
velop policies, select the appropriate EAP design, and 
identify strategies for program promotion, training, and 
casefinding. Members should have sufficient formal and 
informal power and authority to ensure that committee 
decisions will be acceptable to the workforce at large. Sub- 
sequent to program implementation, the committee is to 
operate in an advisory capacity only, leaving program de- 
tails to those so hired, and it must continually evaluate 
both the effectiveness and the necessity of its advisory 
function. 



EAP Goals 

While companies initially pursue an EAP with some 
rationale in mind, it is important that these become for- 
malized goals prior to program implementation. Such goal 
setting clarifies both the scope of the proposed program as 
well as its limitations, and establishes guidelines for the 
development of policies and procedures. Several goals 
have been identified that are characteristic of EAP's in the 
mining industry (1 ). These goals include reducing prob- 
lematic on-the-job behaviors such as absenteeism, acci- 
dents, etc., and increasing worker productivity, providing 
an alternative method for handling disciplinary problems 
linked to employee's personal problems, and increasing 
employee health and well-being. The task at hand is for 
the EAP goals to be clearly identifiable and acceptable to 
all, and to be truly representative of the concerns of the 
organization. 



119 



Policies and Procedures 

Once the EAP goals have been established, they need 
to be incorporated into a written set of policies and proce- 
dures that govern the activities of the program. In prepa- 
ration, present documents need to be examined to deter- 
mine (1) the present policy (or lack of one) on alcohol and 
drugs, (2) the procedures currently used, both formally 
and informally, to handle troubled employees, (3) the 
present employee benefits program, and (4) the current 
personnel practices and union contract. 

The operation of an EAP affects all aspects of the 
company's human resources system, including its policies 
on discipline, absenteeism, alcoholism, and drug abuse. 
Thus, a consistent set of policies needs to be generated that 
is acceptable to labor and management. Because medical 
benefits are likewise implicated, such policies also need to 
be reviewed to reflect the activities of the EAP. Any 
policies drafted must of course address the issue of confi- 
dentiality and must clearly state the scope and limitations 
of such confidentiality. In addition, policy distinctions 
should be made between self-referrals and supervisory re- 
ferrals and the differing confidentiality parameters of 
each. Generally, self-referrals remain entirely confiden- 
tial, unless the employee desires otherwise and signs a 
release form. Supervisory referrals generally require the 
employee to sign a release of general information to the 
supervisor, although this may be waived by the supervi- 
sor. Nevertheless, the general guidelines, and their excep- 
tions, should be clearly delineated. 

Program Design 

The development of program procedures generally 
overlaps with program design, as each influences the 
other. Program design usually requires decisions on (1) 
the population to be included, (2) the types of referrals to 
be utilized, and (3) the provider of the service. 

An EAP can be designed for employees only or can 
include family members as well. While employee-only pro- 
grams are less expensive, family problems are major influ- 
encers of job performance. Once again, the demographics 
of the particular worksite should provide the data neces- 
sary for such a decision. However, most EAP's in the min- 
ing industry include both employees and immediate fam- 
ily (1). 

The next decision concerns the types of referrals to be 
utilized in the system. Here referral defines who can ini- 
tiate help-seeking via the EAP, and there are three possi- 
bilities: (1) management referrals, where the company re- 
quires that the employee seek help; (2) union referrals, 
where labor suggests that the employee seek help; and 
(3) self-referrals, where either the employee, a family 
member, or a coworker voluntarily initiates the EAP con- 
tact. Most generally, all three referral types are encour- 
aged, and a high number of self-referrals is usually the 
hallmark of a successful program. Also, the broader the 
network of potential referral sources, the more effective 
the program is likely to be. 

Once the population to be served has been identified 
and the potential referral sources delineated, the organi- 
zation must decide who will provide the services, the orga- 
nization itself or an outside vendor. The services to be 



provided usually include initial problem diagnosis and as- 
sessment, referral, treatment, followup, and training. 
Companies will differ in the degree to which they wish to 
become involved in actually providing the program serv- 
ices. 

While some larger companies are willing to incur the 
higher costs of establishing an in-house EAP, most pro- 
grams prefer to contract with outside vendors who provide 
the services noted. Such vendors may be localized services 
or those provided on a national basis, and often the pack- 
age is available on a cost per employee, per year basis. 
Although in-house programs can be more finely tailored to 
the needs of the specific worksite, these programs often 
report that employees use them less because of fears that 
confidentiality cannot be assured in-house. This is not 
usually an issue with programs provided off site by con- 
tracted vendors. 



Marketing Strategies 

The expertise of the joint labor-management planning 
committee is invaluable in identifying marketing strate- 
gies geared toward the various constituencies in the work- 
place. Supervisory training, employee training, and the 
training of other special groups (labor relations, person- 
nel, safety, medical department) are strategies that both 
introduce the program concept and clarify its appropriate 
usage. Likewise, various types of printed media are obvi- 
ous ways to foster program awareness and acceptance and 
include brochures, letters to employees, letters to the 
families, posters, and articles in the company and/or em- 
ployee or union newsletters. Such materials should be dis- 
tributed on more than one occasion. 

These formal communication methods must also be 
reinforced by more personal communication methods, such 
as meeting with different employee work groups and work 
shifts, to allow a more informal exchange of program infor- 
mation. Such meetings may include relevant films or 
videotapes. Special organizational events can also be uti- 
lized for program promotion — luncheons, awards ban- 
quets, union get-togethers, etc. 

EAP marketing strategies can become as creative as 
is allowable. However, without sufficient attention- 
getting maneuvers that are sustained over time, a poten- 
tially successful EAP can wither from neglect. 



ORIENTATION AND TRAINING 

Once the EAP concept has been accepted, the program 
designed, and the necessary policies and procedures devel- 
oped, the stage is set for the orientation and training of 
employees, supervisors, management staff, and union rep- 
resentatives. This is the most effective method for educat- 
ing all levels of the workplace on the EAP, its policies and 
procedures, referral process, and confidentiality. Such 
awareness training can be utilized to instruct employees 
on various aspects of mental health and mental health 
difficulties, how to spot these difficulties, and the impor- 
tance of seeking help for these problems before they esca- 
late. Resistances to help-seeking can also be addressed. 



120 



The orientation of employees also serves an important 
marketing function and has been shown to increase both 
the number of self-referrals and the number of coworker 
referrals (3 ). Because more than half of the referrals to an 
EAP generally fall into these two categories, the impact of 
orientation training cannot be overestimated. It is also 
important that training be conducted periodically. The 
more exposure to the program, the more likely that self- 
referrals will continue. 



Given that identification of deteriorating job perform- 
ance usually falls to the first-line supervisors, training is 
important in providing them with the tools necessary to 
(1) identify job performance problems, (2) confront the 
problem employee, (3) refer to the program, and (4) orga- 
nize employee followup. Once again, this training should 
be conducted periodically in conjunction with the com- 
pany's personnel or human resources department. 



KEY PROGRAM COMPONENTS 



This section will delineate in more detail three compo- 
nents crucial to the success of an EAP: (1) the EAP coordi- 
nator, (2) the supervisor, and (3) the voluntary referral. 
Although these elements have been introduced earlier, 
they are significant enough to warrant further discussion. 



EAP COORDINATOR 

The EAP coordinator is responsible for assessing all 
referrals coming into the program and for subsequently 
linking these individuals and/or families with the appro- 
priate treatment providers in the community. The EAP 
coordinator maintains contact with the treatment 
providers and establishes an appropriate system of client 
followup. This followup communication includes regular 
personal contact with the client as well as periodic written 
or oral reports to the company about the client's general 
progress if the EAP referral was company-supervisory ini- 
tiated because of deteriorating job performance. 

In cases where an employee has had inpatient psychi- 
atric or chemical dependency treatment, the EAP coordi- 
nator's job becomes one of easing the employee back into 
the work setting with as little trauma as possible. One 
effective way of doing this is to initiate a return-to-work 
conference that brings together the treatment counselor, if 
possible, the employee, and the employee's supervisor to 
discuss issues surrounding the employee's resumption of 
work responsibilities (4). The employee can be updated on 
events at work, job performance issues existing prior to 
treatment can be addressed, and any other employee or 
supervisor concerns can be identified. 

The EAP coordinator's role obviously requires a thor- 
ough knowledge of available community resources and full 
understanding of the company's insurance policies and 
benefits. In addition, the coordinator is usually involved in 
marketing activities and training, and must keep some 
basic statistics on EAP utilization. However, as discussed 
previously, only in the case of company-supervisor refer- 
rals for deteriorating job performance does the coordinator 
discuss a particular case with anyone other than the treat- 
ment provider. To ensure the utmost confidentiality, the 
coordinator should be housed in a neutral location outside 
of the company setting. 



THE SUPERVISOR 

Supervisors are in an ideal position to do something 
about employees whose job performance may be deterio- 
rating because of off-the-job problems (5). Given their re- 



sponsibilities for monitoring and evaluating job perform- 
ance, they are ususally the first to see declining work 
habits. In addition, the supervisor has the tools available 
to create the crisis so often needed to motivate a troubled 
employee to seek help — the disciplinary procedures of the 
organization. Thus, the supervisor becomes a key mecha- 
nism for communicating the company's plan to the em- 
ployee and for motivating the employee to participate in it. 

To fulfill such a vital role, supervisors need to be ade- 
quately trained in the policies and procedures of the EAP, 
in using criteria to identify, evaluate, and document job 
performance, and in communication skills for effectively 
encouraging troubled employees to seek assistance. Train- 
ing should also emphasize that the supervisor is not ex- 
pected to diagnose employee personal problems nor to re- 
frain from using the usual disciplinary actions as needed. 
The EAP referral is an additional option for the supervisor 
and one that may be employed in conjunction with the 
necessary discipline. 

The process of supervisory intervention entails some 
key behaviors: (1) problem identification, (2) employee 
confrontation, (3) referral for assessment, and (4) treat- 
ment and followup. 

Problem Identification 

Given the primary role of supervisors to plan, orga- 
nize, direct, and control workers in the service of produc- 
tion goals, they become empowered with both the opportu- 
nity and the responsibility to observe and act on employee 
behaviors that are in violation of company policy. Because 
appropriate worker behavior is defined by the job perform- 
ance criteria established by the organization, deviations 
from these norms are described in terms of these criteria — 
absenteeism, tardiness, poor quality work, etc. The super- 
visor is not responsible for diagnosing a worker's personal 
problems in terms of mental health concepts. That is the 
role of the EAP coordinator. The supervisor's role is to 
identify deviations from acceptable job performance. 

Once such an identification has been made, the super- 
visor has two alternatives. Firstly, he or she may decide to 
keep an eye on the situation and see if it resolves itself. 
Secondly, he or she may confront the employee, wait to see 
what happens, reconfront if the poor performance contin- 
ues, and refer the employee to the EAP. Two methods have 
been found helpful in identifying the point at which an 
employee's performance indicates a problem (5). One 
method focuses on changes in previous patterns of any 
employee's work behavior. Significant deviations from the 
normal established pattern for that employee indicate that 
a problem is likely developing. Another method compares 



121 



an individual's work behavior with the norms for the 
worksite as a whole. Significant deviations from the group 
norms suggest that something is askew. 

Both of these methods rely on the documentation of a 
performance decline as the evidence that there is a job 
performance problem. Without such documentation there 
is no verifiable proof that something is amiss requiring the 
services of the EAP. 



support and protect the employee's position once the em- 
ployee agrees to seek help and that the supervisor supports 
the return of the worker to his or her position should an 
absence be required. In come cases, the supervisor may 
directly relate to the EAP personnel regarding an em- 
ployee, within the confines of confidentiality, and may 
take a more active role is an employee's transition back 
into the workforce. 



Employee Confrontation 

Once the deteriorating job performance has been iden- 
tified and documented, the supervisor may decide to con- 
front the employee with the documented deficiencies. A 
request is made for the employee's return to an acceptable 
level of job performance, with or without the involvement 
of the EAP. When confronting an employee, the supervisor 
must communicate both a sincere desire to help and the 
certainty of disciplinary action if poor job performance 
continues. It is also important to confront the employee 
before it is too late. A verbal warning should be issued as 
a job performance issue becomes apparent. 

Employee Referral 

Referral occurs when the problem cannot be resolved 
within the supervisory framework and a confrontation has 
not been effective in mobilizing change. Within the usual 
disciplinary framework, the EAP provides the supervisor 
with an alternative to the shape-up or ship-out approach 
(5), provided the supervisor is aware of the option. At this 
point, the employee either accepts the referral to the EAP, 
or rejects the referral. In either case, the employee will 
experience the typical disciplinary action if job perform- 
ance does not return to acceptable levels within a reason- 
able amount of time. 

Employee Treatment 

The supervisor is least involved in this stage of the 
EAP process. However, it is important that the supervisor 



THE VOLUNTARY REFERRAL 

While much emphasis is placed on the role of supervi- 
sory referrals in the success of an EAP, the actuality is 
that most EAP referrals are either self or family referrals 
or referrals by coworkers. This fact makes voluntary refer- 
rals the mainstay of most successful EAP's and suggests 
that activities found to be helpful in encouraging such 
referrals are well worth the effort. In addition, a self- 
referral usually occurs before the problem has begun to 
affect work performance and thus represents the ideal 
EAP situation. 

Employee training is a most effective marketing tool 
and has already been discussed, as have other publicity 
methods. These methods must repeatedly emphasize the 
confidentiality of self-referrals, as must the EAP coordina- 
tor's behavior when receiving them. Self-referrals are also 
more likely to occur when the diagnostic sessions are free 
of charge. This sets up an atmosphere of perceived com- 
pany involvement and concern that is more conducive to 
employees' taking responsibility for addressing personal 
issues. 

Employee trust emerges over time as the program 
proves itself to be worthy. Satisfied consumers are the very 
best advertisement, and a few test cases are required be- 
fore a general acceptance can be expected. Positive em- 
ployee experience with the program, coupled with ongoing 
orientation, training, and publicity will heighten aware- 
ness, generate referrals, and create a firm EAP founda- 
tion. 



PROGRAM MAINTENANCE 



Program maintenance requires developing a flexible 
plan that will sustain a level of meaningful EAP activity. 
Four strategies for maintaining high visibility include (1) 
ongoing marketing efforts, as have been discussed, 
(2) personnel updates and briefings, (3) program monitor- 
ing, and (4) community resource linkages (6). These activ- 
ities are usually conducted by the EAP coordinator. 



PERSONNEL UPDATES AND BRIEFINGS 

Updates and briefings keep all supervisors, union 
stewards, and other involved personnel informed about 
the current state of the EAP. This keeps the important 
players aware and serves to generate positive feelings 
about the program. Such interorganization meetings also 
provide a forum for discussions and suggestions about the 
EAP services, and for updates on EAP training events, 
meetings, and activities. 



PROGRAM MONITORING 

Routine monitoring of the EAP caseload and referral 
flow can provide early cues as to the evolving nature of the 
program. This monitoring process includes (1) collecting 
referral contact forms and analyzing these data, (2) docu- 
menting both verbal and written feedback on program 
services, (3) studying referral networks within the organi- 
zation to discern patterns of use, and (4) comparing refer- 
ral methods to determine the more effective procedures. 



COMMUNITY RESOURCE LINKAGES 

Effective program maintenance depends upon quality 
working arrangements with a wide variety of community 
resources. These working alliances are evaluated in a 
number of ways: (1) by personally visiting those agencies 
in the area that might provide r>ppr)e>r) cervices. (2) hv 



122 



screening particular agencies according to criteria deemed 
important for effective and efficient employee usage, and 
(3) by monitoring employee satisfaction with the commu- 
nity resource services provided (6). Ultimately, employee 



trust in the program is fostered by employee satisfaction 
with the program, and program monitoring makes possi- 
ble program evaluation. 



PROGRAM EVALUATION 



Goodman (1 ) proposes an evaluation model for assess- 
ing EAP effectiveness in the mining industry that utilizes 
three categories of variables: inputs, processes, and out- 
comes. Inputs refer to the employees who are being treated 
by the EAP, and evaluation concerns the level of aware- 
ness and usage of the program by the employees. Obvi- 
ously, a program can be considered effective if the individ- 
uals who need the services are aware of and utilize the 
services. 

Processes involve those services rendered by the EAP 
and include diagnosis, referral, followup, and training. Ef- 
fectiveness ratings would examine (1) the existence and 
comprehensiveness of EAP policies and procedures, (2) the 
thoroughness of policy distribution, (3) the level of em- 
ployee knowledge of the program, (4) the system for com- 
municating with and educating the employees and super- 
visors about the program and how to use it, and (5) the 



accuracy of referrals made and existence of a followup 
process. 

Outcomes are those problematic job behaviors that the 
EAP is designed to alter or remediate by resolving off-the- 
job difficulties. Such behaviors include accidents, absen- 
teeism, low productivity, grievances, etc. A comparison of 
rate of frequency of these behaviors pre- and post-EAP 
implementation could provide an estimate of program 
effectiveness in countering problem behaviors. 

Although often an afterthought, program evaluation 
is essential in allowing an EAP to grow, change, and mod- 
ify its processes to meet the requirements of the worksite. 
As such, the purpose of evaluation is not only program 
justification. Without it, even the finest of programs can 
become unresponsive to the changing needs of the work 
environ. Only formal, systematic evaluation addresses a 
program's need for feedback. 



CONCLUSIONS 



The mining industry, as well as others, is reaching out 
to its troubled employees and is formulating new ways to 
restore them to a healthly, productive state. The national 



concern for optimal mental and physical health has found 
its way into the workplace, and tbe employee assistance 
concept is one programmatic answer. 



REFERENCES 



1. Goodman, P. S. Research To Determine the Feasibility of 
Utilizing Employee Assistance Programs for the Mining Indus- 
try — Final Report (contract J0100069, Carnegie-Mellon Univ.). 
BuMines OFR 73-86, 1986, 234 pp.; NTIS PB 86-227089. 

2. Wrich, J. T. The Employee Assistant Program. Hazelden, 
1974, 96 pp. 

3. Archambault, R., R. Doran, T. Matlas, J. Nadolski, and 
D. Sutton-Wright. Reaching Out: A Guide to EAP Casefinding. 
Performance Resource Press, Inc., 1982, 92 pp. 



4. Singer, G. Return-to-Work Conference Eases the Way. EAP 
Digest, v. 6, No. 3, 1986, pp. 45-49. 

5. Googins, B., and N. Kurtz. The Role of Supervisors in Occu- 
pational Alcoholism Intervention. EAP Digest, v. 1, No. 3, 1981, 
pp. 14-19. 

6. Gumz, J. A. Is There Life After Implementation? EAP Di- 
gest, v. 5, No. 3, 1985, pp. 27-29. 



123 



EMPLOYEE ASSISTANCE PROGRAMS, BENEFITS OF 

SERVICES, AND ACTIVITIES OF THE MINING INDUSTRY 

SUBSTANCE ABUSE COMMITTEE 



By Frank C. Fantauzzo 1 and Suzanne Smith 2 



ABSTRACT 



This paper was prepared to explain a general employee assistance program (EAP), 
its services, and the benefits of an established EAP at the worksites. In addition, this 
paper discusses the activities of the Mining Industry Substance Abuse Committee. 



INTRODUCTION 



America's workforce is the heart of the nation's econ- 
omy; the health of its members is a matter of national 
priority. Statistics show that the most common cause of job 
difficulties is the excessive use of alcohol or other drugs. 
Statistics also show that up to 75 pet of these troubled 
employees can be returned to productive careers with little 
expense and great benefits to their industries. 3 

Only 531 of the 1.5 million private corporations in the 
United States have alcohol treatment programs and far 
fewer have drug abuse programs. It is time that the myths 
and prejudices surrounding alcohol and drug abuse are 
dispelled and help is offered. Corporations and labor 
unions are finding that programs for the treatment of 
these diseases are of benefit of both employees and indus- 
try in terms of health and job security for the one; in- 
creased productivity and decreased costs in sick pay and 
absenteeism for the other. 

Unfortunately, three-fourths of the Nation's 90.5 mil- 
lion workers are employed in establishments of fewer than 
500 employees; where it is unlikely that either manage- 
ment or the unions will take the initiative in developing 
programs. 



iProject director, Occupational Alcohol Abuse Program. 
2 Director of communications. 
Appalachian Council, Charleston, W V 

3 Cline, S. Alcohol and Drugs at Work, Drug Abuse Council of the Amer- 
ican Public Health Association, Chicago, IL, 1975, p. 4. 



Alcohol alone affects the health and productivity of 
almost 8 pet of any workforce, and thus nearly 5.1 million 
employees in small business. These workers present an 
opportunity and a challenge. Alcoholism and alcohol 
abuse cost the nation nearly $116 billion annually. Sev- 
enty billion dollars is attributed to lost production. Health 
and medical expenditures, as a consequence of alcohol-re- 
lated health problems, are estimated to be $12.7 billion. 

The cost of substance abuse to industry has been esti- 
mated by the National Institute on Drug Abuse (NIDA) to 
be in excess of $4 billion per year. In addition to its eco- 
nomic impact, substance abuse has serious personal and 
social consequences. Human suffering resulting from alco- 
hol and drug abuse is incalculable. 

The need for industrial concern and active involve- 
ment is underscored by the magnitude of these conse- 
quences. 

It is believed that the mining industry experiences, 
though to an unknown quantity, the same exposure to 
alcohol, drug abuse, and other employee problems as other 
industries. However, the existence of these problems poses 
a particular mine safety hazard because of the unique 
conditions found in mining. 

Mining is known as an industry having many safety 
and health hazards, and employees must have full control 
of their faculties and be capable of giving full attention to 
the tasks at hand. 



124 



DESIGN CHARACTERISTICS OF INDUSTRIAL EAP'S 



An EAP is a cost-effective, 4 confidential, early inter- 
vention system designed to help employees with problems 
that interfere with their ability to function on the job. An 
EAP serves to identify and assist employees impaired by 
alcoholism, drug abuse, mental illness, and other human 
problems. An EAP can be very effective because it leads to 
earlier problem identification. 

Studies have shown that procrastination in seeking 
assistance can reduce potential recovery rates from 80 pet 
down to 15 pet or lower. 5 Because the EAP approach 
strives to be nonthreatening to the employee, identifica- 
tion takes place earlier. 



Unions have long been advocates of programs de- 
signed to rehabilitate rather than terminate employees, 
and initial implementation procedures call for labor in- 
volvement at the very beginning. The employer provides 
assurance to the employee that the program's primary 
objective is to help and not to harm him or her. EAP pro- 
grams can be developed in a unionized operation and also 
in a nonunion operation with the same procedures and 
principles. EAP's come in many forms, the purpose of this 
section is to identify several, and initially, programs may 
be formal or informal. 



THE INVISIBLE PROGRAM 



One major factor is the assumption by top manage- 
ment or labor that problem drinking and substance abuse, 
since they are frequently not visible or not reported, do not 
exist within the company or union. Middle and lower man- 
agement or union personnel may conceal cases, since they 
believe that the recognition of such problems will reflect 
badly on their work records. 

The result is that top officials rarely learn of a case of 
problem drinking or drug abuse until the employee's work 
performance has deteriorated sufficiently that he or she 
must be terminated. Management and union heads then 
are deluded by the impression that these infrequent, 
severe cases are the only ones that need to be dealt with. 
Another common assumption is that drug problems are 
limited to younger age groups and that only a very small 
percentage of employees are susceptible to either alcohol 
or drugs, which precludes a realistic assessment of the 
extent of the problem. 

Many companies and unions do not have formal 
policies or procedures for dealing with behavioral prob- 
lems but operate under an informal, covert, word of mouth 
system — usually one of concealment. 

The company will pay economic premiums (in fringe 
benefits, job security, and promotion opportunities) to al- 
coholics and their supervisors for successful concealment 
of the problem from higher levels of management. When 
the alcoholism has reached the point where it cannot be 
concealed from the attention of top management, the alco- 
holic's services will be terminated. This means that indus- 
try often retains an unproductive employee for an average 
of 12 to 17 yr before terminating him or her, will pay out 
large sums in health insurance claims for problems sec- 



ondary to the causal condition, will tolerate increased acci- 
dents, but will not help the employee with his or her basic 
problems. 

The following 29 yr work record (starting in 1957) of 
a troubled employee (table 1) clearly illustrates how such 
an unwritten policy works, and further shows how much 
earlier the problem could have been dealt with by a policy 
of constructive confrontation. 

In 1985, for the first time, successive steps of correc- 
tive discipline of any type were taken with full and proper 
communication between company and union. Offers of 
confidential help made were at each step. After three steps 
of a four-step procedure, employee asked help in admission 
to a substance abuse treatment center. 

This work record shows that not only were early warn- 
ing signs ignored, but that the company's unwritten policy 
actually distorted standard personnel practices. It is also 
noted in table 1 where standard company policies were 
either inconsistent or not followed through. This example 
also demonstrates how in the absence of an agreed policy, 
the company and the unions can work against each other 
to their mutual disadvantage and the employee's detri- 
ment. 

Although the concept of constructive confrontation is 
simple, there are many problems involved in the imple- 
mentation of such a program. 

These stem mainly from the fact that alcoholism and 
drug abuse have an aura of disgrace and shame. As a 
consequence, many organizations labor under an unrecog- 
nized, but active system of nonrecognition and conceal- 
ment. 



WHAT IS A FORMAL EAP? 



A formal EAP has a system of policies, procedures, 
and attitudes, which takes an early positive intervention 
and is based on unsatisfactory job performance. A formal 
EAP offers confidential, approachable help, and is viewed 
as a cost-effective program. This will help provide ways for 



"•Bureau of National Affairs (Washington, DC). Speical Report: Alcohol & 
Drugs in the Workplace: Costs, Controls, and Controversies, 1986, 122 pp. 

■'National Institute of Alcohol Abuse and Alcoholism. Study Utilization 
of EAP's. 1985, pp. 15-16. 



correct referral, treatment, and followup to assure maxi- 
mum rehabilitation for the troubled employee. 

In addition, these programs, whether management or 
union inspired, or staffed by outside consultants, provide 
several types of services. 

1. They create an awareness of the problem. The first 
step in creating a program is the recognition that an alco- 
hol and drug abuse problem exists and it must be dealt 
with. Because of the stigma attached to problem drinking 
and drug abuse, and the unwillingness on the part of those 



125 



Table 1. — Work record of a troubled miner operator 

(Male, age 47 at time admitted for alcoholism treatment (Oct. 9, 1986); 29-yr service (employed Apr. 15, 1957); primary health problem: alcoholism and drug 



dependency) 



Dates 

Apr. 1957-69 . 

1970 

1971 

1972 

1973 

1974 

1975 

1976 

1977 

1978 

1979 

1980 

1981 

1982 

1983 

1984 

1985 

1986 



Events 



Personnel records and fringe benefits claims showed nothing unsatisfactory or unusual. 

Jaw fracture (off the job); 3 episodes of flu, colds — 9 days off; $168 insurance claims. 

Garnishment. Back pain; 2 episodes of flu, colds — 5 days off; late for work 4 times, excuses: car trouble, sick child, car trouble, family 

trouble. 
Acute bronchitis — 10 days off; late for work 6 times, verbal and written warnings given; 2 failures to report off, written warning, Nov. 

1972, that 1-day suspension would occur on next offense; $56 insurance claim. 
Failed to report off in January, verbal warning; 1 sore throat, nausea, upset stomach, nervousness, colds, absences totaled 18 days 

in 1 - to 3-day periods; 4 tardies with excuses of car trouble, family sickness, etc. 
Sickness absences, 19 days; tardy 3 times; failed to report off twice; 3-day suspension given, union protested too severe, reduced 

to 1 day. 

Off the job accidents; $376 insurance claims, gastritis, nervousness, colds, trips to nurses aid station for medication. 
Written warning about absenteeism and laxity in reporting off, 1 3 months of fairly good record then absenteeism pattern resumed; 

garnishment (2). 

Sleeping on the job, written warning; off during long strike. 
Off the job — auto accident, $235 insurance claims, garnishment; headache, cold, flu, stomach trouble, car trouble, nervous 

conditions, 29 days lost time. 
Discovered he could get elixir terpin hydrate at doctor's office by pleading throat infection: record of 42 such requests during the 

next 6 yr; began taking vacation time in small chunks, often tied to beginning or end of sickness or personal absence. 
Discovered that by getting a doctor's slip at start of illness could avoid most warnings and suspensions; found an aged physician 

who signed easily and examined little; uncle died — said he had to help settle estate, 8 days absent. 

Garnishments (3); sleeping on the job; insubordination; chronic absenteeism — dismissed; union protested; reinstated — "last- 
chance" agreement signed by company and union. 
Death in family, 7 days absent; car accident, $49 insurance claims; tardy twice; acute gastritis; 24 days absent, $633 insurance 

claims. 

Garnishments; gastritis; reported for work intoxicated, verbal warning. 1 
Sickness-absences, 24 days. 
Company and union agreed to general policy on alcoholism and related problems. Steps taken to begin developing motivation and 

assistance measures. Acute gastritis; $802 insurance claims; garnishments, sleeping on the job, usual absenteeism patterns, 1 

verbal warning; off-the-job accident; $32 insurance claims. 
Memorandum that machine downtime had been excessive during the past 2 yr; 1 summary of absenteeism and disciplinary actions 

in 1985 made; sleeping on the job; reporting for work intoxicated. 



1 Standard company policies either inconsistent or not followed through. 



in authority to acknowledge such difficulties in their com- 
panies, recognition is by no means an easy step. 

2. They educate. These programs educate both labor 
and management on the scope and nature of the problem. 
They learn that alcohol and drug abuse are treatable con- 
ditions and that the workplace is a good place for imple- 
menting a successful program. The programs illustrate 
the effectiveness of constructive confrontation and the tan- 
gible advantages to both the employee and the company — 
the former through improved health and continued em- 
ployment, the latter through increased productivity and 
profits. 

3. They necessitate organization. These programs re- 
quire the company and the union to take organized action. 
The normal disciplinary and reporting systems of both are 
restructured to accommodate the policy of constructive 
confrontation — to establish formal steps for dealing with 
those who need help. Supervisors, shop stewards, manage- 
ment, and employees are alerted to the fact that these 
procedures are in effect and are informed of their respec- 
tive roles. 

4. They refer. A working relationship is established 
between local businesses and community resources. The 
program provides a linkage for referral, treatment, and 
rehabilitation. 

5. They follow up. Each employee's record in the pro- 
gram is evaluated. The program should determine if treat- 
ment and rehabilitation were effective and ensure that 
maximum benefit is achieved for both the company and 
the employee. 

FORMAL EMPLOYEE ASSITANCE PROGRAM 
COMPONENTS— POLICY AND PROCEDURES 

The policy agreement should be one signed by the 
chief executive and chief union representative where ap- 
propriate. The function of their agreement will be to pro- 



vide a clear statement of the purpose, incentives, and ben- 
efits of the program. The agreement will provide a basic 
frame of reference that is essential, both in development of 
procedures to be followed on implementing the policy, and 
as a guide for uniform administration of all elements of the 
program. It encourages the individual's voluntary utiliza- 
tion of the program by the assurance of confidentiality, job 
security, adequate insurance coverage, and acceptance of 
the disease concept of alcoholism, drug abuse, and mental 
disorders. 

The policy statement and procedure will serve as a 
valuable training tool for all union and management per- 
sonnel involved in implementing the policy itself. 



Confidentiality 

The written rules should be established specifying 
how records are to be maintained; for what length of time; 
who will have access to them; which information will be 
released to whom, and under what conditions; and what 
use, if any, can be made of records for purposes of research, 
evaluation, and reports. Employee records maintained by 
an EAP should never become part of an employee's person- 
nel file. The record-keeping files should be designed to 
protect the identity of the employee, while facilitating case 
management and followup and providing ready access for 
statistical information. 



Team Work 

Some formal EAP's, mainly in large corporations, em- 
ploy an in-house counselor, or subcontract to local mental 
health hospital or local counseling clinic. The responsibil- 
ity for the EAP counseling it to coordinate the EAP pro- 
gram. 



126 



The counselor should show concern and interest for 
the employee, yet, motivate this person to explore the pos- 
sibilities of treatment. The responsibility of the EAP con- 
selor is to identify an employee's problem. The profes- 
sional mental health counselor or medical professional is 
able to diagnose alcoholism and substance addition. 
The EAP counselor should — 

Have current listings of agencies and services for treat- 
ment; 

Insure confidentiality; 

Work with an EAP worksite joint-committee of manage- 
ment and labor; and 

Arrange visits to treatment agencies for the joint com- 
mittee for knowledge and evaluation. 

Joint (Management and Labor) Committee 

A joint committee of the workforce organization 
should be formed of equal numbers representing manage- 
ment, union employees (if the employees are organized), 
and nonunion employees. This in-house committee follows 
an outline of agreed-upon procedures. 

The joint committee will secure effective cooperation of 
all agencies within the community and evaluate which 
provide treatment services. 

The joint committee will develop a record-keeping sys- 
tem that assures confidentiality to employees. 

The joint-committee will approve any training program 
for company supervisors, union representatives, and EAP 
counselors. All training should take place with company 
and union representation attending at the same time. 

The joint committee will assess the program on a regu- 
lar basis and make changes where appropriate. 

Awareness Programs 

All employees and their families should be informed 
about the organization's EAP and the services it offers. 
Educational techniques should be employed to provide up- 
date information on the EAP and its benefits. The infor- 
mation should be mailed to the employee's home. 

A training program should be developed for all levels 
of supervisors, labor representatives, and joint committee 
members, which will assure implementation of the pro- 
gram. 

Such a program could include — 

An explanatory message from a responsible individual. 

A short film that is designed to acquaint the supervisors 
and labor representatives with a better understanding of 
illnesses covered under the EAP services and methods of 
referrals to professional counseling or diagnostic services. 

A clear definition of the responsibilities of the supervi- 
sors and labor representatives with respect to the proce- 
dures with which they are charged in implementation of 
the program. 

Use of charts or visual aids in instruction on procedures 
to be followed including: 

1. Proper documentation and evaluation of unsatis- 
factory work, work performance or behavior, and of all 
corrective action taken. 

2. Clues and record reviews to use in determining 
deteriorating work patterns. 

3. Importance of firm and consistent application of 
standard corrective procedures. 

4. Proper channels of communication with higher 
line authority, labor representatives, industrial relations 



staff, and EAP coordinator when supervisors are in doubt 
as to appropriate action. 

Information about the existence of EAP and its pur- 
poses should be available for all employees, through an 
ongoing orientation program. 



Job Performance 

The advantages of the job performance approach are 
Supervisor only evaluates performance. 
Earlier intervention. 
No new skills required. 

Clear, simple policy for dealing with difficult problems. 
Labor and management both share gains. 
Significant cost benefits. 



Benefits of EAP 

The following are benefits of an EAP for both labor 
and management. 





Labor 




Management 


1. 


Genuine personal 


1. 


Organization's 




benefits for mem- 




demonstrated inter- 




bers and their 




est in the welfare of 




families. 




its employees is 
valuable to creating 
a good public im- 
age. 


2. 


Fewer grievances. 


2. 


Fewer grievances. 


3. 


Fewer accidents. 


3. 


Fewer accidents. 


4. 


Less money spent in 


4. 


Less money spent in 




disputes. 




disputes. 


5. 


Improvement in 


5. 


Improvement in 




morale of members. 




morale of members. 


6. 


Less absenteeism. 


6. 


Less absenteeism. 


7. 


Decline in medical 


7. 


Decline in medical 




cost means a saving 




cost because of ac- 




for the union. 




curate diagnosis of 
alcoholism and/or 
addiction. 


8. 


Better labor- 


8. 


Better labor and/or 




management rela- 




management rela- 




tions. 




tions. 


9. 


Better relations 


9. 


Cost saving: em- 




among union mem- 




ployee rehabilita- 




bers. 




tion for fraction of 
the cost of a re- 
placement. 


10. 


More referrals when 


10. 


Effective approach to 




program has credi- 




a problem hereto- 




bility with union 




fore ignored or de- 




membership. 




nied. 


11. 


General educational 


11. 


Reduction of stigma 




effect of program for 




when a problem 




members and their 




goes from the tool- 




families. 




room to the board- 



room. 



12. Job saved. 



12. Increased productiv- 
ity. 



127 



MINING INDUSTRY SUBSTANCE ABUSE COMMITTEE 



The Mine Safety and Health Administration (MSHA) 
academy in Beckley, WV, has received inquiries from var- 
ious segments throughout the mining industry concerning 
alcohol and substance abuse in the mining industry. The 
Director of MSHA formed a committee to deal with these 
inquiries. The committee met in April 1985, at the mining 
academy in Beckley, 

This committee expanded its membership to represent 
labor, management, and Government agencies affiliated 
with the mining industry, and national Government agen- 
cies dealing with alcohol and drug abuse. This expanded 
18-member committee met for the first time in July 1985, 
at which time two cochairmen were elected. One was from 
management, the other from labor, to oversee the mining 
industry substance abuse committee. 

At this point, the Mining Industry Committee on Sub- 
stance Abuse, (MICSA) has spent considerable time on 
education by sharing information on the issues, and by 
calling in outside experts for advice and consultation. As 
this internal educational process has progressed, the com- 
mittee has initiated several projects. First, the committee 
is developing a resource manual on substance abuse and 
employee assistance programs that can be used as models 
or guides by mine operators and/or labor unions. Second, 
the committee is assembling statistics on substance abuse, 
particularly as applied to mining. Third, the committee 
has commissioned an educational film, Substance Abuse, 
Is It Our Problem. This film, produced by MSHA, is an 
introduction to the problem of substance abuse in the min- 
ing environment. The basic thrust of the film is to encour- 
age mine operators, labor unions, and miners to analyze 



their individual circumstances to determine whether a 
problem exists. Additionally, the film offers ways to deal 
with the problem, when it exists. Finally, the film invites 
the industry to request additional information from 
MICSA. 

There is no single approach to substance abuse that 
will fit the need of every mining operation. Remedies must 
be site specific just as with any safety, health, or produc- 
tion problem. On the other hand, the mining industry has 
long been known for the ingenuity it brings to the prob- 
lems of mineral extraction, transportation, and process- 
ing. There is every reason to expect that the same ingenu- 
ity can be brought to bear on substance abuse, and shared 
throughout the mining community. 

MICSA's aim is to channel solutions derived from that 
characteristic ingenuity to those in the industry who seek 
to help employees in the mining environment who want to 
rid themselves of alcohol and substance abuse. 

The MISCA's members have agreed on the following 
mission statement: 

The Mining Industry Committee on Substance Abuse 
represents the combined efforts of labor, management, and 
Government. The mission of the committee is to make the 
mining industry aware of the problems resulting from al- 
cohol and other drug abuse within the industry and to 
recommend possible methods to remedy the problem. The 
function of the committee is to assist the industry in devel- 
oping programs and resources to recognize and provide 
help for troubled employees, and thus reduce the risk of 
accidents, lower absenteeism, and increase productivity. 



SUMMARY 



1. The concern about alcohol and substance abuse in the 
mining industry is there. 

2. All organizations in the mining industry want to 
work together to solve the problem. 



3. A method of addressing the problem will be pre- 
sented to the industry in 1987. 



128 



FACILITATING SUPERVISORY PERFORMANCE: 
A WORKSHOP APPROACH 



By Ronald Althouse 1 and James A. Peay 2 



ABSTRACT 



Training may be regarded as the process of acquiring skills and knowledge for the 
performance of an activity. It is particularly important to organizations in terms of 
both resources expended on training and benefits resulting from subsequent perform- 
ance. The effect of training in the mining industry is especially important because of 
widespread reliance on appropriate worker behavior to minimize the risks associated 
with mining processes. 

The distinguishing feature of the training effort reported in this paper is its focus 
on assisting small-mine management in dealing with identified training needs for 
section supervisors and other supervisory personnel in day-to-day operations. Al- 
though the mining industry has had to absorb considerable responsibility for the 
initiation, modification, and continuation of training programs, the structural capabil- 
ities for implementing these programs seems to depend in part upon the size of the 
mining operation. 



INTRODUCTION 



The Bureau of Mines reports that more than 60 pet of 
the mining operations in the United States employ less 
than 50 people. Because small mines do not have the sup- 
port personnel found in the management structure of 
larger operations, it has not yet been determined whether 
small mines have substantially different supervisor train- 
ing needs. If consistent, useful training resources are to be 
fashioned, training needs and training environments for 
small mines have to be assessed. 

The Mining Extension Service of West Virginia Uni- 
versity (WVU) received Bureau support for the develop- 
ment of mine management training materials for small 
underground mines. Two functions were performed: (1) a 
need assessment and (2) curriculum development. Often, 



'Associate professor, Sociology; and research associate, Mining Exten- 
sion Service, COMER West Virginia Univ., Morgantown, WV. 

Supervisory engineering psychologist, Pittsburgh Research Center, 
Bureau of Mines, Pittsburgh, PA. 



projects dealt with only one of these two functions, assess- 
ment or materials development. Benefits of the twofold 
program were that the designers would have a heightened 
awareness of the small-mine operation as well as knowl- 
edge of the potential audience, and at the same time, the 
materials would be relevant and could be assessed in the 
field. 

The foundation for a sound assessment 3 includes: 
(1) sufficient communications to establish achievable and 
unambiguous objectives, (2) an analysis of the job to 
understand the skills needed to perform required tasks, 
(3) an evaluation of compatibilities (previous experience 
and/or capability measures) to help choose training media 
and allocate appropriate time for training, and (4) the 
identification of the limitations of the training program 
and the training environment. 






3 Goldstein, I. L. The Pursuit of Validity in the Evaluation of Training 
Programs. Human Factors, v. 20, No. 2, 1978, pp. 131-144. 



129 



ASSESSING SMALL-MINE NEEDS 



Characteristically, the small mines were comprised of 
a single conventional or continuous section crew; some- 
times a mine operated two shifts. At times the mine oper- 
ators managed the section; sometimes they did not boss. 
However, section responsibility for labor control and for 
factors affecting cost and quality were part of their experi- 
ences, and were not obscured by competing rules of disci- 
pline. 

Repeated interviews with operators led to the forma- 
tion of a set of commonly recognized operational and safety 
responsibilities (specific details of section foremen duties), 
which provided a measure for deciding what information 
to incorporate into the training materials. After supervi- 
sor task information was obtained through interviews, ad- 
ditional information was obtained from questionnaires 
sent to small mines. 

Results from this assessment seemed to indicate that 
small mines have made limited training investments. 



They often lacked the know-how necessary to plan train- 
ing programs and to improve safety programs. Moreover, 
small-mine operators felt that complying with State and 
Federal training regulations was costly, and they usually 
opted to minimized such costs by turning to outside train- 
ing sources (e.g., private training, consultants, educa- 
tional institutions). 

On the other hand, attempts to identify priority needs 
for safety programs and training showed there was little 
clarity about the performance expected from supervisory 
personnel, and consequently, few objectives were identi- 
fied by operators for training programs and information. 
The assessment revealed that other features of mine oper- 
ations often regarded as perplexing to small-mine man- 
agement dealt with labor relations, management skills, 
and engineering problems. 



TRAINING RESOURCES 



What training medium is appropriate for small 
mines? Classroom training was viewed unfavorably and 
considered highly impractical. Mine operators resisted 
programs that would interrupt production. Sending super- 
visors for training was considered to be such an interrup- 
tion. Any problems dealing with know-how were solved in 
the context of the tasks at hand. Thus, many operators 
regarded easy -to-read informational guides as the best for- 
mat for personnel. 

While it was not feasible to deal with all the needs 
expressed by the operators, in many cases, the guides that 
were developed addressed more than one need. Seven 
guides were developed in a concise, learner-directed for- 
mat, designed to be low in cost. They could be used as part 
of instruction on a topic or as a source of information for 
individual self-study. Written in a down-to-earth, 
straightforward manner, the content assists individuals in 
becoming more effective in their work. Brief descriptions 
of each guide will help to explain their scope and intent. 



GUIDE NO. 1— HUMAN RELATIONS 
SKILLS AT WORK 

This guide is designed to help mine supervisors deal 
with on-the-job human relations problems. Part 1 dis- 
cusses human relations problems and the role of the super- 
visor. Part 2 provides practical suggestions for handling 
specific situations that often arise with miners on the job. 
Results showed that 68 pet of the mines had no human 
relations training for management, 92 pet were not cur- 
rently conducting training, but 60 pet expressed a need to 
provide training at their mines. 



GUIDE NO. 2— MANAGING A SECTION 

Designed to help section supervisors carry out their 
duties effectively, this guide deals with the management 
of section crews for safety, operations, and compliance 



with Federal and State regulations. Useful information 
and tips are provided to assist supervisors with their 
duties and responsibilities. This guide was prepared in 
response to (1) labor management training needs — 54 pet 
had not provided training, 92 pet did not provide training, 
yet 52 pet wanted this training; and (2) time management 
and/or planning the work day needs — 72 pet had not pro- 
vided training, 96 pet did not provide it, but 54 pet felt the 
training was needed at their mine. In many small mines, 
the section foreman was the only management level per- 
son normally inside the mine during the working shift. 



GUIDE NO. 3— COMPLYING WITH PART 48 

The guide provides an overview of Federal training 
programs. Included are mandated topics, training plan re- 
quirements and certification, a sample training plan, how 
to evaluate your trainer, and how to become a certified 
mine trainer. Because Federal regulations require that 
every mine provide training for all miners, the guide 
serves as a reference for small operators, providing a 
clearer understanding of the regulations and a means to 
achieving more benefit from training efforts. 



GUIDE NO. 4— CONDUCTING YOUR 
OWN TRAINING 

Mine owners and operators who want to conduct 
training are the target group for this guide. Topics include 
characteristics of the adult learner, how to develop useful 
learning objectives, instructional methods and using 
visual aids, and utilization of lesson plans. Setting up a 
training room, alternative delivery systems, and evaluat- 
ing training progress are also covered. Emphasis is on 
keeping training up to date. Information showed that for 
more than half the mines, annual refresher training was 
conducted by private firms; only 40 pet conduct any of 



130 



their own training. As many as one-third felt they were 
not getting their money's worth from training invest- 
ments. 



GUIDE NO. 5— ELEMENTS OF MANAGEMENT 
PLANNING 

This guide provides an introduction to managerial 
planning and control, and is geared to owners and opera- 
tors of mines with relatively few management level peo- 
ple. Operations planning and control are described; part 2 
relates control to planning, and it introduces tools of in- 
come and cash-flow management. Results indicated that 
many operators received little or no formal training in 
management practices, learning to manage operations 
through experience. Management training-educational 
assistance was one of the most often identified needs 
(89 pet). 



GUIDE NO. 6— MANAGING MAINTENANCE 

Managing maintenance draws on practical sugges- 
tions of mine operators, maintenance supervisors, electri- 
cians, and mechanics. Part 1 suggests steps for building an 
effective maintenance plan. Part 2 contains tips on carry- 
ing out maintenance and housekeeping procedures. 



Seventy-seven percent of the respondents indicated a need 
for an effective maintenance program, the highest rated 
on the assessment. In addition, maintenance problems 
were mentioned as the single, most salient problem in 
mine operations. 



GUIDE NO. 7— DEVELOPING A COMPREHENSIVE 
SAFETY PROGRAM 

Intended to help operators develop a mine safety pro- 
gram that is both mine-specific and comprehensive, mate- 
rials deal with the structure and components of a safety 
program as well as ideas on how to evaluate specific needs 
and build a program that will be effective and reliable. 

Few small mining operations had developed a formal- 
ized, documented approach to their safety and training 
efforts. By using the procedures and suggestions presented 
in this guide, operators can develop and institute a safety 
program suited to the particular needs of their mine and 
responsive to changes in mine conditions. This guide was 
systematically employed to link the rules and regulations 
for the West Virginia Comprehensive Mine Safety Program 
(WV Administration Regulations, Department of Mines, 
Chapter 22-4, Series 33) with operator reports submitted 
annually to the State by each mine. As a guide, its practi- 
cal usefulness and scope as well as its basis for measuring 
safety performance and improvement is highly recognized 
on a statewide level. 



STEPS TO IMPLEMENTATION 



Mining Extension Service (MES) efforts to follow up 
on the uses of the new training resource showed two typi- 
cal paths chosen by an operator: it was used (1) as supple- 
mentary handout material distributed during annual or 
mandated supervisory training, or (2) as reference mate- 
rial built into and supporting training on a topic. While 
the first avenue turns out to be an easy way to disseminate 
materials, results are inconsequential; a followup canvass 
dealing with 37 mine operations employing about 65 sec- 
tion supervisors showed that almost no one read these 
guides, and few even examined them to decide if anything 
useful was included. 

Of the 33 section foremen contacted during the fol- 
lowup canvass, only 42 pet (14) were able to identify any 
one of three guidebooks provided to them (Guide No. 1 — 
Human Relations, Skills at Work, Guide No. 2 — Managing 
a Section, and Guide No. 6 — Managing Maintenance). 
Nearly all of the section foremen contacted claimed these 
materials were helpful, yet only 9 pet (3) were capable of 
correctly identifying any content provided in the materials 
(e.g., planning equipment downtime, trouble-shooting, 
keeping on sights, conducting safety observations). Five 
reported they had given some material to other supervi- 



sors or associates, and nearly half (15) claimed that they 
had discussed some material contents with another super- 
visor since the training meeting when the guidebook ma- 
terials were distributed. Nonetheless, there was little in- 
formation from the followup canvass of foremen to 
support, in fact, that materials had been read, let alone 
used and discussed. 

The second approach — using materials selectively as 
reference during training — was observed only twice, but 
had better results. Guide No. 6 — Managing Maintenance 
was employed to help specify a high-priority management 
goal for the operators' mines. Specific procedures for su- 
pervisory performance on maintenance jobs were selected 
by the operator. However, the guidebook material was 
treated merely as a reference, without tailoring the objec- 
tives of their maintenance program to incorporate the con- 
tent. In the authors' estimate, such use at least stimulated 
recognition of a need for maintenance planning and pro- 
vided some suggestive procedures. Followup review 
showed that several employee participants did consult the 
material to gauge their activities and monitor experi- 
ences. 



131 



THE WORKSHOP IMPLEMENTATION 



A third option emerged for exploring training ar- 
rangements. This process involved tailoring small mine's 
materials to allow each trainee to bring his or her own 
experience to bear on a set of problems. 

This project was deliberately designed to address the 
needs of smaller mine operators located within a particu- 
lar area. Called the Boone County Mine Management 
Training Project, it was administered by a committee com- 
posed of six mine operators. A key State and a Federal 
representative provided advisory assistance to the opera- 
tors. The program was arranged to provide 8 h of training, 
organized into four 2-h sessions. It was available to every 
section supervisor or management person in the county. 
About 700 individuals were eligible to participate, of 
which 120 supervisory persons (roughly one-fifth) partici- 
pated during the first two rounds of the workshop pro- 
gram. The following discussion focuses on these two 
rounds. 

The overall training objective was to provide a vehicle 
through which mine supervisors could collectively iden- 
tify, discuss, and share solutions to the problems encoun- 
tered in day-to-day section operations. MES staff were 
committed to mobilizing resources, focusing areas of per- 
formance, maintaining continuity, and producing the 
workshop. In effect, the project was an implementation of 
a training protocol, based on a distinctive set of materials. 
The workshop plan was consciously guided by Goldstein's 
four-step assessment scheme. 

A workshop format, rather than a formal classroom 
lecture technique, was used in the training sessions. The 
sessions were based on the premise that problem solving is 
facilitated by problem recognition, and that answers are 
usually choices made from recognized alternatives. It was 
felt that for every foreman who encounters a problem, 
there is another section foreman who has overcome a sim- 
ilar problem; therefore, supervisors could learn from each 
other. Learning how to recognize problems and how to 
examine alternative courses of action to mediate or over- 
come problems seems essential to any supervisory plan- 
ning. 

To invite active participation in discussions, an initial 
session was scheduled for each workshop group. By design, 
learning groups had to be a sufficient size to ensure a 
range of experience and still foster participation from each 
person. A format was needed that would inspire individual 
commitment to the efforts of the group. The procedure that 
was employed was to "nominalize" the group during the 
first session, and then to build on each group's specific 
experiences during the remaining four workshops. A nom- 
inal group process requires a small number of partici- 
pants; each group was limited to 12 persons. Because fore- 
men worked all shifts, morning, afternoon, and evening 
workshop sessions were organized on different days to ac- 
commodate mining operations. Arranging the partici- 
pants into five groups satisfactorily met the size require- 
ment. No group comprised more than two or three 
supervisors from any one mine operation. 

The first session, when the nominalizing was accom- 
plished, focused on responses to the instruction "Please list 
the most important opportunities for safely improving op- 
erations in your mine." Each participant listed as many 
opportunities as reflected on the experiences provided to 
him or her. A roundrobin followed and each member con- 
tributed until no additional proposals were forthcoming. 



The list was reorganized and condensed. Each participant 
was asked to select seven important safe productivity op- 
portunities and to rank them from the most to least impor- 
tant. The 10 most important opportunities to safety 
improve operations were evaluated in three ways: (1) Dif- 
ficulty (easy or hard to do), (2) frequency (frequently or 
seldom encountered, and (3) availability of needed re- 
source or skill. All participants were asked to consider the 
priorities to reassess tactics discussed, and to begin the 
following session based on outcomes of the meeting. Each 
operator whose supervisors had participated received a 
copy of all workshop results. Each of these operators was 
asked to rate the list and to assess the listed recommenda- 
tions concerning implementation. 

By using results from the initial session, illustrative 
material was chosen to focus on in the four subsequent 
meetings. The program finally selected was the following: 
Week 1. — Establishing efficiency on the section 

A. Consider value of effective planning 

B. Develop a work system whereby duties and tasks 
function in unison 

C. Anticipate and utilize downtime effectively 

D. Foresee problems and limit their impact 
Resource: Guide No. 2 — Managing a Section 

Guide No. 6 — Managing Maintenance 
Supervisor Responsibilities: Operating, Safety, and 
Compliance (see Appendix) 
Week 2. — Human Relations 

A. Review principles of human relations 

B. Motivate the workforce 

C. Resolve disputes and conflicts 

D. Earn the respect of the workforce 

E. Give each worker the responsibility of his or her 
job 

Resource: Guide No. 1 — Human Relation Skills at 
Work 
Week 3. — Safety roles and responsibilities of the section 
supervisor 

A. Set the standards for safety on the section 

B. Provide a good safety example through own work 
habits and practices 

C. Control and/or eliminate safety hazards on the sec- 
tion 

D. Assure compliance with company policies, Federal 
and State regulations 

E. Analyze accidents and take proper remedial ac- 
tions 

Resources: Guide No. 4 — Conducting Your Own 
Training 

Guide No. 7 — Establishing a Comprehen- 
sive Safety Program 

Supervisor's Jobs — How Risky Are They? 
What the Stats Show. (MSHA Magazine 
Winter-Spring 1984.) 
Week 4. — Understanding State and Federal Regulations 

A. Keeping up to date on regulations 

B. Knowing what the inspector expects on your sec- 
tion 

C. Keeping your required records up to date 
Resources: Code of Federal Regulations (30 CFR) 

West Virginia Mining Bulletin 

West Virginia Mining Laws 

West Virginia Administrative Regulations 



132 



USING GUIDEBOOK MATERIALS 

Several examples illustrate how these resources were 
meshed. Performance improvement efforts were specifi- 
cally focused upon during the workshops. Thus, for exam- 
ple, an examination of results from the initial session sug- 
gested that understanding State and Federal regulations 
was essential to compliance goals and objectives. It was 
decided to provide each person with 30 CFR, West Virginia 
Mining Bulletin, West Virginia Mining Laws, and West 
Virginia Administrative Regulations. In regard to safety 
and compliance goals, an attempt was made to break out 
of the lockstep mold of "token compliance" to regulations. 
Supervisor-foreman safety and the proposed tactics for 
loss-prevention and damage control (i.e., direct and indi- 
rect costs) were examined. These concerns were condensed 
into a set of materials for one session. 

Practical features of foremen responsibilities and 
their dealings on the job were taken from practical appli- 
cations. A lead-in discussion focused on the authority of 
section foremen. Foremen know they are responsible for 
production on their section and are held accountable for 
the safety of workers assigned to them. On the other hand, 
they express varying degrees of awareness and under- 
standing about company policies that must be followed. 
Experience shows that foremen are results oriented; con- 
sequently, they may do their work without attention to 
subsystems or practices that could aid them. 

One useful example focused on a section foreman 
whose shuttle car operators were running on damp, soft 
roadways. Past experience and present demand naturally 
informs the foreman that the roadways must endure for at 
least 1, maybe 2 weeks. A few days later, the section has 
unnecessary downtime for shuttle car tram delays. The 
foreman must now explain to the mine operator the rea- 
sons for downtime for shuttle car tram delays, as a result 
of ruts in the roadway. The operator knows that conditions 
on the section should not have resulted in these delays. 

In small-mine operations, work procedures are not 
usually based on articulated planning. Most loss- 
prevention and damage-control analysis can show that 
both employee exposure to hazards as well as equipment 
breakdown are among the outcomes associated with lack 
of planning. However, the foreman may not have been 
prepared to control the situation by monitoring conditions 
of roadways, by avoiding travel over the same tracks, or by 
advising operators to fill developing ruts. The effect of 
failing to anticipating these conditions usually is an in- 
crease in management errors. There are no plans of action 
to combat conditions, to direct the operators to adjust their 
actions, nor to control the developing situation. 

A second dimension of the workshop focused on the 
responsibilities of management to support its supervisory 
personnel. Operational practices need to be tailored to an 
organization, detailed, and fully imparted to personnel 
who must use them. Anticipation, planning, task support, 
and management interaction are persistent features of co- 
ordination. More complicated jobs entail more thorough 
planning. The foreman is involved in arranging resources, 
organizing tasks, and scheduling work events. He or she 
has to coordinate other workers to supplement labor. 
Above all, he or she has to anticipate how to control, step- 
by-step, the rate of task and/or job completion in spite of 
changing conditions, equipment breakdown, or other de- 
velopments that can impede work. Assessment of actual 
versus planned steps is made, and correction actions need 



to be anticipated to keep on schedule. Knowledge of the 
jobs to be done, how they need to be done, and when they 
need to be finished is essential to the foreman's mission. 

Section foremen are instrumental in controlling daily 
output and are pivotal in maintaining good labor- 
management relations. To secure the consent of workers to 
perform their work according to preferred procedures, the 
foremen must be consistent in performing their jobs. They 
need to plan section moves and anticipate delays that re- 
sult from deteriorating conditions or equipment failures. 
Supervisor demands will need to fit those performances 
that can be realized by workers. The foremen must be 
consistent in their own expectations, in training their per- 
sonnel, in assigning tasks fairly, in "keeping pay," and in 
ensuring safety. Their authority can be exercised when 
their leadership is acknowledged by the crew; leadership 
is acquired after consistent management is demonstrated. 

Throughout the workshop the participants were able 
to examine procedures, their successes and shortcomings, 
and points of change in practices. Self-check lists for super- 
visors are useful when coupled with performance feedback 
(daily, weekly, and monthly production and downtime re- 
ports, grievance status reports, accident and citation sum- 
maries). Examples of self-checks were shared and criti- 
cized in the workshops. The prime objective of self-checks 
is to force ongoing comparison between actual and planned 
performance. The information is useful to formulate pre- 
ferred ways to achieve operational objectives. 



SECTION SUPERVISORS' RESPONSIBILITIES 
AND AUTHORITY 

Each participant had been provided with a list of su- 
pervisory responsibilities, organized according to operat- 
ing, safety, and compliance duties (appendix). It was possi- 
ble, therefore, to direct attention to common expectations 
and to the competing and conflicting demands frequently 
experienced by section foremen in performing their jobs. 
Moreover, by recognizing responsibilities and what ac- 
tions occurred during preshift, start-of-shift, on-shift, end- 
of-shift, and post-shift operations, concern was focused on 
planning and communicating skills. Foremen were urged 
to examine the list to determine which duties were routine 
or not, which were easy or hard to do, and what authority 
was required to gain consent or secure compliance. This 
permitted each workshop group to contrast current prac- 
tices against proposed improvements and upgraded per- 
formances. 

One strategy for improving section supervisor per- 
formance is to arrange duties in chronological order span- 
ning a typical production shift, directing attention to the 
way foremen must perform and the way they think about 
their jobs. In small mines, one- or two-section operations, 
it is precisely such information that is often informally, 
and sometime quite haphazardly, gathered. Presumption 
and habit dominate in these operations. The process forces 
supervisory personnel to match and contrast personal 
practice with preferred performance. 

The initial phase of work, before the shift begins, finds 
the foremen gathering information from the previous shift 
to determine the needs of the upcoming shift and formulat- 
ing a work plan. Based on this plan, they check the status 
of resources and arrange resource availability on their 
shift. They coordinate their section plans with the general 



133 



foremen or other production, maintenance, and staff man- 
agers. They monitor the check-in of crew members and 
obtain fill-in labor as needed. 

At the start-of -shift, the foremen make an inventory 
of section conditions, equipment, resources, and opera- 
tional readiness on arrival at the section. Crew members 
assist the inventory. Any significant revisions in the 
workplan depend upon the accuracy of observed condi- 
tions. The foremen initiate required section examinations 
simultaneous with the inventory, before face operations 
begin. The tempo for the rest of the shift's operations is set 
at this time. 

Operations comprises the bulk of the foremen's shifts. 
Production cycles typically bring into coincidence several 
of their duties and produce overlapping responsibilities 
that are managed simultaneously. These responsibilities 
pertain to 

1. Operations, including production, maintenance, and 
downtime. 

2. Compliance with State and Federal mining laws. 

3. Health and safety of workers, including training. 

4. Labor relations, including communication and ad- 
ministrative accountability. 

The foremen are the keys to exercising labor disci- 
pline and to securing its consent to authority; they are 
essential to maintaining a smooth running operation. 
They monitor the flow of work throughout the shift and 
direct cycle-by-cycle adjustment in face operations. They 
must effectively plan ahead of face operations but keep up 
with routine regulatory duties as well as abnormal dis- 
turbances. 

Ensuring that work gets done safely is a weighty re- 
sponsibility for the foremen. There are always convenient 
ways to get a job done easier than preferred work prac- 
tices, but shortcut ways usually are not safe. Not every 
way to reduce the work effort is hazardous, yet many 
shortcuts are known to increase risk of exposure or injury 
to oneself or a coworker. 

Cross-analysis strategies can be used to restructure 
experience into chains of events that encourage anticipa- 
tion and planning. Because miners must learn to mine coal 
safely, they can be taught preferred safe work procedures, 
and they can learn to correct those actions that get them 
into trouble. 

At the end-of -shift, the foremen execute a routine 
thorough shutdown of the section, complying with regula- 



tions, controlling physical and equipment conditions, and 
fully coordinating with oncoming shift supervision. The 
post-shift is used to wrap up the day's activities. The fore- 
men's work includes accurately reporting production, 
downtime, and ancillary work completed. They process 
pay sheets for employees, coordinate with the oncoming 
shift, and indicate resource and equipment repair require- 
ments. They identify operating problems warranting at- 
tention in the future (immediate, intermediate, and longer 
term plans) and they complete all reports in official record 
books. Before finishing their day, it is important that the 
foremen follow up on any promises made to an employee. 



BENEFITS OF EFFECTIVE TRAINING 

The primary objective of the workshop program was 
improvement of frontline supervisor performance under 
varying situations. Gains would afford better operations, 
thus improved safety and productivity of the section crew. 
These goals can be achieved by section foremen who mas- 
ter management techniques, tactfully exercise authority, 
and possess the know-how to execute responsibilities. 

Resulting benefits (i.e., measures) include (1) im- 
proved control of section operations, (2) more consistent 
compliance with mining laws, (3) reduction of unnecessary 
delays to production, (4) reduction of accidents and lost 
employee-days, (5) reduction in the number of employee 
grievances, (6) decrease in absenteeism, (7) improvement 
of crew motivation, (8) better teamwork and unified ac- 
complishment of common goals, (9) better crew prepared- 
ness in responding to critical situations, and (10) continual 
progress toward improving the mining system. 

A reactive, hit-and-miss approach to foremen develop- 
ment occurs too often and fosters operations in which fore- 
men expend their energy trying to stay out of trouble. 
Preparation of section foremen reduce their vulnerability 
to inexperience as well as inadequate knowledge of the 
requirements of their jobs. When foremen are unprepared, 
they are prone to make decisions that can and do jeopar- 
dize operations and subject them to criticism from their 
crews. The building of an operation that encourages im- 
proved performance results in a better chance at achieving 
success. 



DISCUSSION OF THE WORKSHOP EXPERIENCE 



At the time the workshops were being conducted, the 
coal mining industry was undergoing considerable re- 
alignment among management-supervisory personnel, 
and was experiencing many mine closings. Section fore- 
men as well as working miners were confronted with the 
ultimate dictum of discipline — choosing between work 
and no work — and were directly impressed with the fact 
that production was essential to keeping a job. As a matter 
of fact, during workshop sessions conversations repeatedly 
drifted to talk about record production, although fewer 
miners were employed than in the recent past. Moreover, 
each of the small mining operations from which the work- 
shop participants were drawn was operating with a bonus- 
incentive wage program. Each operator reported that in 



addition to incentive, their employees were paid top wage 
scale. Thus, for these operations, production assured 
bonus, and bonus was normally attainable with a fairly 
high degree of certainty. 

In these small mining operations, section foremen 
were in the same boat as their miners with regard to con- 
tinuing employment. Confronted with dwindling employ- 
ment options and attainable, although high, production 
goals, but boosted by incentive wages, foremen and work- 
ers found considerable inducement to collaborate and 
achieve consistently high output. These supervisors were 
aware that unless the mine operators who employed them 
endorsed any of the techniques and procedure addressed in 
the workshop materials, they would not be accountable for 



134 



any new proposals. The study observations, quite frankly, 
suggested that there was little reason to expect the section 
foremen to change any ways of action at their mines unless 
explicitly directed to do so by the operator. Where training 
was largely regarded as cumbersome regulation, typically 
assigned to peripheral personnel or outside contractors, 
workshop materials were not approved and options were 
disregarded. 

The situation was oftentimes different for foremen 
drawn from larger, more complex mine operations. In the 
larger firms, organizational forces produced different vul- 
nerabilities for section foremen. Job rivalries put them 
into situations in which their own equals were heavy com- 
petitors; when realignments hit, who did or did not stay 
depended on what "appeared" to foremen as discretionary 
actions by layers of management above them. Their own 
production crews attempted to get greater latitude (e.g., 
taking shortcuts), so they felt they were working harder 
than ever to keep up production. Because mine operations 
management was likely to tighten demands, they also felt 
they were obliged to make greater investments in retain- 
ing their positions. Moreover, there was visible evidence of 
threat to their security: bosses who had attained ranking 
positions (e.g., shift bosses) were back on production sec- 
tions. Based on a number of followup contacts with fore- 
men from several large mines, a strong inclination toward 
disengaged participation in workshop activities was 
found: participation was an assignment, and attendance in 
the workshop produced the marginal investment (compli- 
ance) that at least protected them from exposure to man- 
agement. 

In larger mines, where full-time specialists are 
charged with the responsibility to obtain appropriate be- 
havior from employees engaged in the mining process, 
"property rights in materials" are very likely to be highly 
protected, vested interests. The workshops inadvertently 
invaded that training territory, precisely at a time when 
job security was a tender issue for many staff employees. 



Secondly, and correctly, most of the company operations 
had corporate-approved training programs geared to their 
firms. Training was planned and executed by the com- 
pany, providing foremen with information that invested 
responsibility as senior management deemed appropriate: 
in these programs there was no outside interference with 
their proposals and concomitant procedural rules. 

The workshops potentially legitimized information 
(e.g., the comprehensive safety program) and procedural 
guides to actions (e.g., grievance or accident investiga- 
tions, loss-prevention) that contrasted, sometimes con- 
flicted with company rules. It was learned also through 
followup contacts with management, that rules are made 
and orders given to foremen, that are not arrived at 
through discussion. But is is also realized that manage- 
ment training programs now in use were produced to han- 
dle newcomers to the ranks of frontline supervision during 
a period of industry expansion. These materials reflect 
poorly the operating conditions of the industry today and 
veteran supervisors may not find them useful at all. 

There is no reason to expect new departures in operat- 
ing practices as a result of these workshops. They were 
immeasurably more effective in reaching supervisors, or 
gaining attention from them for a short period of time, 
than other distribution techniques seen elsewhere. De- 
pending upon the immediate degree of success personally 
experienced by the supervisor, certain elements of the 
workshop could be diffused among the supervisory work- 
force. Ways to attack maintenance or housekeeping prob- 
lems, to curb downtime, to deal with comprehensive safety 
efforts, and to reflectively plan by anticipating preferred 
performance and action from miners on their sections did, 
indeed, catch the attention of participants. 

These workshops were supposed to be building blocks 
for a continuous training model that should have been 
incorporated into the Boone County Mine Management 
Training Program. When management commitment 
dwindled, continuity eroded for the workshop program. 



CONCLUSIONS 



While the small mines management training project 
chalked up several accomplishments, it also experienced a 
share of shortcomings — some were dealt with but others 
lingered and even grew worse with time. First, the work- 
shop may be a more viable technique for smaller opera- 
tions than for larger operations; at least, this was the 
experience. Second, there was a remarkable variety of ex- 
perience and capabilities among section foremen, which 
lead to a concern about prerequisite skills (e.g., mapping, 
print reading, hydraulics, job instruction training abili- 
ties). Another consideration was redundancy and distrac- 
tion; future training and the selection of problems to study 
would have to be based on much more precise performance 
results, using proven strong programs or procedures as 



criterion. Fourth, followup on the consequences of the 
training was difficult — some followup was attempted, but 
actual outcomes depended heavily on the operations, and 
there was no assurance of adoption or implementation. 
Finally, when committee support eroded, the program was 
difficult to maintain; if management support was strong, 
participation endured. 

A measure of the relevance, if not the success, of the 
Bureau-sponsored small mines management project is ev- 
ident in the fact the Mine Safety and Health Administra- 
tion (MSHA) has packaged and is distributing the entire 
package of materials as well as the workshop curriculum, 
virtually without change or modification of the Boone 
County program, as Industry Supervisory Training. 



135 



APPENDIX.— LISTING OF SECTION SUPERVISOR DUTIES 



I. Preshift Duties 

1. Arrive 1 h early to allow ample time for good coor- 
dination. 

2. Dress immediately to avoid interference with coor- 
dination later. 

3. Read over previous shift reports for production, 
maintenance, examinations, violations, and supply requi- 
sitions for your section. 

4. Get report on pagerphone from on-shift foreman 
regarding — 

a. Status of equipment-maintenance work needed. 

b. Equipment locations in the mining cycle. 

c. Status of physical conditions and/or operational 
problems. 

d. Work that needs to be accomplished. 

e. Compliance problems. 

f. Employees staying in between shifts for any rea- 
son. 

g. Signature of mine examiner book with report. 

5. Monitor check-in of personnel. 

6. Convey status of section to shift foreman; coordi- 
nate on-shift requirements. 

7. Make request for extra or temporary employees. 

8. Make sure crew members are properly equipped 
(clothing and tools). 

9. Communicate conditions on sections to crew mem- 
bers. 

10. Coordinate at mine map with previous shift sec- 
tion foreman, shift foreman, mine foreman, and superin- 
tendent. Discuss important matters openly. 

11. Notify extra or temporary personnel of job assign- 
ment and if special equipment is needed. 

II. Start-of-Shift Duties 



13. Examine working faces for — 

a. Deenergized equipment and location. 

b. Air quantity at inby end of brattice and/or 
tubing. 

c. Condition of ventilating checks, brattice and/ 
or tubing. 

d. Methane, roof, rib, and floor conditions. 

e. Safety and compliance. 

f. Conditions that need correcting (and note 
them). 

g. Supplies on equipment, 
h. Sight lines. 

i. Cleanup and dustiness. 

j. Necessary cycle moves (fan, cables, stopping, 
etc.). 

14. Give instructions to crew members as needed; note 
revisions to initial plan and conditions requiring caution 
in correctng them. 

15. Determine status of equipment, cables, materials 
from crew members who checked them in a general way. 

16. Set power on equipment if ready and operable; 
begin repair of equipment that is not operable and coordi- 
nate for additional mechanics and/or electricians as 
needed. 

17. Coordinate dumping of supplies that are loaded 
during face run; ensure adequate amounts were loaded; 
load any necessary unplanned for supplies; check servic- 
ing of equipment. 

18. Report any unplanned occurrences to shift fore- 
man and/or dispatcher. 

19. Record the nature and duration of unplanned oc- 
currences (delays). 

20. Give task training and/or description of escape- 
ways and firefighting duties to temporary or extra person- 
nel. Practice safe performance of tasks as necessary. 



1. Ensure entire crew catches mancage as scheduled. 

2. Check mantrip for all safety and operational re- 
quirements. 

3. Check safety of crew on mantrip — 

a. No body parts outside mantrip. 

b. Operators outside mantrip wear glasses. 

4. Start inby to work section (calling dispatcher as 
required). 

5. Travel at safe speed, at proper distance, and in full 
control. 

6. Note unsafe road, roof, rib, support conditions and 
report to shift foreman and/or dispatcher. 

7. Keep haulage switches in proper position on the 
way into section. 

8. Deboard in a proper and safely guarded place. 

9. Have mantrip parked at designated place. 

10. Ensure walkway is well kept and safe. 

11. Give safety talk, if proper time (weekly). 

12. Check roadways and intersections on the way to 
first face for roof, rib, and floor conditions, rock dusting, 
cleanup, and dustiness. 



III. On-Shift Operational Duties 

A. Production Related Cycle 

1. Monitor initial move to first cut; ensure sight line 
is in and used; ensure extra brattice-ventilation tubing, 
spads, wire, tools are ready; ensure shuttle car operators 
use correct haulroads (closest changeout) and have enough 
cable for entire cut. Ensure personnel are coordinated on 
plan. 

2. Monitor loading of first couple of shuttle cars to 
ensure smooth start and note any problems (physical, op- 
erational, or mechanical). 

3. Report start time to dispatcher, also state probabil- 
ity for loading well and anticipated problems. 

4. Return to cut before time for place change and coor- 
dinate move. Note any changed conditions and give warn- 
ings to workers who will enter places, if necessary. 

5. Plan ahead for cable moves, fan moves, keeping up 
with sight lines, cleanups, rock dusting, etc. Coordinate as 
necessary. 



136 



6. Report any problems or needs immediately to dis- 
patcher and shift foreman. 

7. Repeat steps 1 through 6 for each cut when possi- 
ble. 

8. Keep track of all delays to production immediately 
and accurately for use on shift report. 

B. Health and Safety Actions 

1. Monitor crew members in the performance of their 
jobs and ensure safe work practices are used faithfully. 
Follow up with reinstruction as needed. 

2. Ensure workers use proper attire and safety equip- 
ment and tools for conditions encountered. 

3. Ensure workers use proper tools and equipment for 
job and also properly operate them. 

4. Observe workers for inconsistent performance and 
possible drug or alcohol effects. Counsel with discretion 
privately, as necessary. Personal problems may also affect 
performance. 

5. Use caution and give warnings in a new or rare 
situation; observe closely for hazards and anticipate sup- 
plemental actions that may be needed to combat the haz- 
ards. 

6. Ensure employees report all accidents, equipment 
damage, and close calls. Report them, in turn, to shift 
foreman at appropriate time. 

7. Ensure that an injured employee goes out if serious 
injury is possible. Call dispatcher to arrange transport. 

C. Labor Relations Practices 

1. Maintain control of operations; provide steady and 
consistent direction of workers. 

2. Communicate with workers and other managers; 
inform workers of actions and decisions; coordinate with 
workers and managers for fulfilling needs of section. 

3. Do not participate in spreading gossip. 

4. Respect abilities of workers and solicit their input 
on specific tasks. 

5. Talk over incipient grievances privately; sort out 
details and try to settle in accordance with contract. Talk 
over personal problems with workers who seek help. 

6. Ensure accurate and timely paydays for workers. 

7. Keep track of contract leave days and unexcused 
absences for crew members, caution them privately and 
tactfully regarding indiscretions, and remind them of dis- 
ciplinary provisions of contract. 

8. Keep alert and energetic. This mental conditioning 
rubs off on workers. 

9. Equitably assign extra and downtime jobs to work- 
ers. 

10. Make only promises you know you can keep, fol- 
low through promptly and accurately on them; be fair to 
all crew members. 

D. Compliance Actions 

a. Ventilation-Escapeway Provisions — Daily 

1. 20-min methane examinations at working faces. 

2. Examinations at faces every 2 h. 

3. Air readings at faces and returns. 

4. Mine examiner report on section following exami- 
nations. 

5. Ensure escapeway signs and directional markers 
are up. 



6. Ensure adequate rock dust maintained in escape- 
ways and rest of section. 

7. Ensure escapeway map is up to date on section. 

8. Ensure dust control methods are maintained — 

a. Sprays on equipment. 

b. Roadways wetted if necessary. 

c. Equipment washed down. 

d. Belt tailpiece and feeder maintained. 

9. Keep water pumped down on section. 

10. Maintain brattice and/or tubing within 10 ft of 
face. 

b. Roof Control Provisions — Daily 

1. Ensure bolting pattern is maintained within toler- 
ance. 

2. Use supplemental support as conditions warrant. 

3. Ensure "1 of 10" and "1 of 4" bolt torque checks are 
made. 

4. Ensure temporary roof support on bolting machine 
makes contact with roof. 

5. Ensure posting and cribbing patterns are main- 
tained on pillar extraction, watch for changing conditions. 

6. Use wooden headers on bolts for greater bearing 
surface when needed. 

7. Maintain sight lines to ensure consistent pillar 
sizes. 

8. Use rib support where needed. 

9. Maintain longer bolts and posts on section. 

10. Check roof by drilling one hole 1 ft longer each 
cut. 

11. Ensure maximum cutting width is not exceeded. 

12. Ensure sum of diagonal distances at an intersec- 
tion is less than maximum allowable distance. 

13. Report unintentional roof falls for investigation 
and mapping; rehabilitate according to posted plan. 

14. Discard resin that exceeds shelf life immediately. 

15. Follow intersperse pattern for change from resin 
to conventional bolting, and vice versa. 

16. Do not exceed cut depth. 

17. Follow plan for recovering supports during pillar 
extraction. 

18. Ensure proper tools are available (sounding de- 
vice, torque wrench, slate bar, etc.). 

19. Follow cut sequence within tolerances. 

c. Electrical-Permissibility Provisions — Daily 

1. Ensure equipment plugs and receptacles at power 
center are marked and matched. 

2. Ensure restraining clamps or chains are on trail- 
ing cable. 

3. Ensure warning signs for high voltage are up. 

4. Ensure necessary rubber mats are in place at 
power center breakers. 

5. Ensure permissibility is maintained for equip- 
ment, pumps, heaters, etc. 

6. Ensure temporary splices are fixed before next day 
and no temporary splices exist within 50 ft of a machine. 

7. Ensure all bonds are installed on rails along track 
(rail-to-rail, cross bonds 200 ft, switches). 

8. Watch for arcing between machines. 

9. Ensure cables are hung and guarded where 
needed. 

10. Keep equipment clean. 

11. Maintain fire extinguishers and rock dust (240 lb) 
at permanent electrical installations. 

12. Ensure equipment is safe to run (guards, etc.). 



137 



13. Ensure end of trolley wire is secured and guarded. 

14. Ensure trolley wire is guarded at mandoors and 
mantrip unloading stations. 

15. Use insulated hangers for hanging cables. 

d. Miscellaneous Provisions — Daily 

1. Ensure workers are fully task trained and it is 
documented. 

2. Ensure accumulations of coal and dust are cleaned 
up. 

3. Ensure two sources of communications are work- 
ing properly. 

4. Ensure portable water is maintained on mantrip 
and in section. 

5. Ensure ample first aid supplies are available. 

6. Maintain clean and unobstructed walkways. 

7. Ensure manholes are cut as required along track. 

8. Ensure workers keep self-rescuers with 25 ft and 
self-contained self-rescuers are available on section. 

e. Weekly Provisions 

1. Make necessary bleeder station examinations and 
enter in report book. 

2. Ensure weekly permissibility examinations are 
completed for all equipment on section and properly docu- 
mented. 

3. Ensure methane monitor calibration is completed 
and documented. 

4. Conduct safety meeting and document it. 

f. Monthly Provisions 

1. Ensure smoking articles check is made and docu- 
mented. 

g. Quarterly Provisions 

1. Ensure escapeways are walked and documented. 

2. Ensure fire drill is conducted and documented, 
h. Annual-Semiannual Provisions 

1. Ensure 8-h retraining is given to personnel. 

2. Report any ideas for revisions to roof control or 
ventilation plans. 



IV. End-of-Shift Duties 

1. Stop cutting in sufficient time to leave section in 
full compliance with mining laws. 

2. Leave section in good condition for next foreman; 
report all problems fully and accurately (equipment down, 
poor conditions, etc.). 

3. Do not leave section early — you are finishing cut- 
ting or moving too early; economic survival may someday 
depend on extra 10 min of operation. 

4. Ride out in mantrip as you rode in — orderly and 
controlled. 

5. Ensure no horseplay occurs at cage or elevator, 
which can injure workers. 



V. Postshift Duties 

1. Make out shift report professionally and com- 
pletely. 

2. Coordinate with mine foreman and superintendent 
at mine map; report workers left in, labor relations prob- 
lems, and operational problems; mark section map up to 
date; identify near-term section needs such as power cen- 
ter move, track advance, planking, stopping, belt move, 
etc. 

3. Fill out paysheet accurately and place in proper 
distribution box. 

4. Coordinate with maintenance regarding any me- 
chanical problems, even if small. 

5. Fill out and sign mine examiner and assistant 
mine foreman books. 

6. Fill out and sign additional report books as re- 
quired (smoking articles check, safety talks, bolt torque, 
bleeder station examinations, escapeway travel, fire 
drills). 

7. Perform any followup promised to crew members. 



138 



THE HECLA STORY: ORGANIZATION DEVELOPMENT 
IN THE HARD-ROCK MINING INDUSTRY 



By Cecil H. Bell, Jr. 1 



ABSTRACT 



An organization development (OD) demonstration project, sponsored by the Bu- 
reau of Mines and conducted at Helca Mining Co., showed that OD techniques can 
improve mine safety and productivity. One year after the program began, lost-time 
injuries had decreased 44 pet at the target mine and decreased 8 pet at a comparison 
mine. No effects on productivity were observed at that time. After the program was in 
operation at the target mine for 5 yr, lost-time injury rates had declined by 78 pet, short 
tons per stoping worker shift had increased 54 pet, and short tons per worker shift for 
all labor had increased 32 pet. It is reasonable to attribute some of the improvement 
in performance to the OD program. Team building-problem solving meetings at all 
levels of the organization constituted the principal OD technique used in the program. 
Company members have been trained to conduct these meetings. This paper describes 
the OD program, evaluates its effects, and presents observations on the relevance of 
OD for the mining industry. 



INTRODUCTION 



In 1979, the Bureau of Mines sponsored the first orga- 
nization development (OD) program ever conducted in the 
metal-nonmetal mining industry in the United States. 
The objective was to determine whether OD techniques 
could improve mine safety and mine productivity. The 
project was accomplished under Bureau contract 
J0387230, in cooperation with Hecla Mining Co., Wallace, 
ID. That demonstration program, now in its seventh year 
at Hecla, showed that OD techniques can improve both 
mine safety and productivity. This paper describes and 
evaluates that project. 

OD is a process for causing organizational improve- 
ments based on the belief that organization members 
themselves can identify and solve their major problems, if 
they use systematic procedures guided by an outside con- 
sultant. In OD, organization members examine how well 
they are doing and look for ways to do better. 

Hecla Mining Co. was founded in 1891 and describes 
itself as "the premier silver mining company in the United 
States." It is usually the foremost producer of newly mined 
silver in the Nation. When the project began in 1979, 
Hecla had about 700 employees, operated two major silver- 
lead mines in the Coeur d'Alene district of northeastern 
Idaho (the Lucky Friday Mine and the Star Mine), and had 
several smaller operations in other Western States. Mr. 
William A. Griffith, president and chief executive officer, 
agreed to participate in the Bureau's project in order to 
improve mine safety. 



In broad outline, the Hecla program unfolded as fol- 
lows: the Bureau sponsored the OD demonstration project 
from July 1979 to May 1982, during which time the em- 
phasis was on improving mine safety. The target mine was 
the Lucky Friday Mine, and 1981 was the period of great- 
est activity at the Lucky Friday. The work tasks of early 
1982 consisted of completing the demonstration project 
and writing the final report for the Bureau. In May 1982, 
Mr. Griffith asked the Bureau's contractor to "continue 
the OD program and train our people to do what you do." 

The period since 1982 has been devoted to consolidat- 
ing the program at the Lucky Friday Mine, extending the 
OD effort to encompass other organizational units, and 
training company members to conduct the program. Many 
changes have occurred at Hecla since the OD program 
began. In 1981 Hecla acquired Day Mines, Inc.; in 1982 
mining operations at the Star Mine were discontinued; 
and in 1984 Hecla acquired Ranchers Exploration and De- 
velopment Corp. The company had 945 employees at the 
end of 1985. 

Although OD is used extensively in many industries, 
there have been only a few OD programs in mining, all of 
them with coal mining companies. The most noteworthy 
OD program in mining was the Rushton Coal Mine project 
conducted by Trist, Sussman, and Brown (2 ), 2 using socio- 
technical systems theory. According to these authors, the 
results of the 4-yr program were a reduced number of 
lost-time injuries, improved safety practices, decreased 



Associate professor of management and organization, Graduate School 
of Business Administration, University of Washington, Seattle, WA. 



2 Italic numbers in parentheses refer to items in the list of references at 
the end of this paper. 



139 



production costs, and increased productivity. The program 
was terminated prematurely, however, when the union 
membership voted to discontinue it. An independent anal- 
ysis of the Rushton project by Goodman (2) concluded that 
the effort produced "slight positive gains" in safety and 
productivity, but not the substantial improvements re- 
ported in reference 1. Gavin and Kelley (3) conducted a 
multiyear OD program in a Colorado coal mine and re- 
ported improved employee attitudes and morale as well as 



increased ability to deal with work-induced stress. In sum- 
mary, OD programs in coal mining have been few in num- 
ber, but have usually produced positive results. 

The overall strategy and implementation activities of 
the OD program are presented in the next section. Then 
the results are examined. Finally, conclusions are sug- 
gested and implications for the mining industry are pro- 
posed. 



OVERVIEW AND DESCRIPTION OF THE OD PROGRAM 



This section presents the elements of the OD program 
strategy and a chronological history of the highlights of 
the project. 

PROGRAM STRATEGY AND 
GUIDING PRINCIPLES 

The goal of the demonstration project was to improve 
mine safety and productivity; OD techniques were the 
means, and the time frame was 3 yr. 

The program strategy was developed after several 
months of orientation and diagnosis by the consultant 
team, during which time they learned about the organiza- 
tion's strengths and weaknesses, its preferred modes of 
operating, and its culture and values. The program strat- 
egy, developed jointly with the president and senior man- 
agement team, included the following key elements: 

Conduct a classic OD program. 

Make team building-problem solving the principal OD 
technique used. 

Use additional OD techniques as appropriate. 

Start at the top of the organization and work downward 
through the hierarchy. 

Include hourly employees and their supervisors in the 
program. 

Establish and maintain high program momentum and 
extensive consultant involvement. 

Avoid a one-shot, quick-fix program. 

Focus on task accomplishment; that is, getting the job 
done. 

Address safety issues at all levels of the hierarchy. 

Conduct the program at a "treatment" mine and desig- 
nate a "control" mine to receive no treatment. 

Be successful; do not get fired. 

Conduct a Classic OD Program 

A classic OD program has the following characteris- 
tics: it is a long-term effort; it is conducted by an outsider 
who is trained to understand organizational dynamics and 
know how to change them; the intervention plan is devel- 
oped and implemented based on a thorough diagnosis of 
the organization; primary emphasis is placed on examin- 
ing and changing the culture and processes of work teams 
to help them function better; considerable effort is spent 
working on real, high-priority problems and opportunities; 
and such programs are deliberately consultant-intensive. 

Make Team Building-Problem Solving 
the Principal OD Technique Used 

Classic OD programs follow the problems wherever 
they lead, and OD interventions are developed for the 



problems identified. That was done at Hecla. Additional 
interventions used were: individual coaching and counsel- 
ing; individual and team goal setting; safety experiments 
and analyses; first-line supervisor training; behavior mod- 
eling skills training for middle managers; intergroup 
problem solving and conflict resolution; role analysis and 
clarification; operations management studies; a goal 
setting-performance feedback experiment; performance 
appraisal training; OD facilitator training; and team prob- 
lem solving skills training for line managers. 

Start at the Top of the Organization and 
Work Downward Through the Hierarchy 

Successful OD programs are managed from the top 
(4). Hecla's president not only managed the entire pro- 
gram, he gave it strong support and was actively involved 
as a participant. Team building meetings began with the 
president and senior management team and progressed 
down the operations department to include the vice presi- 
dent for operations and the operations team (which in- 
cluded the mine managers), the Lucky Friday mine man- 
ager and the mine top management team, the Lucky 
Friday mine manager and mine production team (which 
included first-line supervisors called shift bosses), and ap- 
proximately one-half of the hourly employees. This down- 
ward progression ensured that each team leader had al- 
ready been involved in team building meetings at a higher 
level, knew what to expect from the meetings, and was 
comfortable with the team building process. 

Include Hourly Employees and 
Their Supervisors in the Program 

Safety and productivity ultimately occur where the 
pick hits the rock; therefore, the program had to include 
the shift bosses and crews. Attitudes and behaviors had to 
be changed at that level, but encouraged and supported by 
higher levels. 

Establish and Maintain High Program Momentum 
and Extensive Consultant Involvement 

Successful OD programs have a sense of momentum, 
excitement, and accomplishment that is established early 
and maintained throughout. Early successes are sought 
that will spark this sense of progress. The diagnostic inter- 
views got the momentum started. Next the consultants 
designed a new performance appraisal system, trained all 
the raters who would use it, and the system was imple- 
mented. Team building meetings were always launched 



140 



with a series of meetings held in rapid succession to pro- 
mote quick, positive results. As soon as team building was 
established at one level, it was extended to the next level 
to promote a sense of urgency and progress. The consul- 
tants made frequent visits to the company: 9 in 1979; 17 in 
1980; 23 in 1981; 14 in 1982; 19 in 1983; 19 in 1984; and 
10 in the first 6 months of 1985. The high level of consul- 
tant participation signaled that the program was impor- 
tant, serious business. 

Avoid a One-Shot, Quick-Fix Program 

From the outset, the president was adamant about the 
nature of the program. The program was for real, not an 
academic exercise; it was intended to produce permanent 
improvements, not quick fixes. The program was to instill 
better ways of managing, not flashy superficial behaviors 
that would be discarded when the program was over. The 
president insisted on a solid, deliberate program, realizing 
it would require hard work by everyone. 



Be Successful, Do Not Get Fired 

This guideline was developed by the consultant for the 
consultant. This was the first time OD had been tried in 
hard-rock mining, and it could well be the last opportunity 
for a long time if the program were a failure. It was about 
equally important to be successful, that is, improve mine 
safety, as it was to avoid failure, that is, have the program 
terminated before it was completed. The program had to be 
valuable for the company; the consultants had to be com- 
petent, relevant, acceptable, and results oriented. The con- 
sultants worked especially hard to ensure that diagnoses 
were accurate, that interventions were timely and well 
executed, and that the necessary formal and informal com- 
munications between clients and consultants took place. 

In summary, these were the key elements of the pro- 
gram strategy conceived prior to launching the interven- 
tion and implemented during the program to guide deci- 
sions and choices. 



Focus on Task Accomplishment, That is, 
Getting the Job Done 

Team building can be task oriented (getting the job 
done better) or interpersonal relations oriented (getting 
people to like each other better) or a combination of both. 
The focus at Hecla was on task accomplishment, not inter- 
personal relationships. A task focus was chosen because it 
is less threatening to people. It is a more natural and 
legitimate activity in work organizations and, when task 
accomplishment is improved, interpersonal relations usu- 
ally improve as a byproduct. 

Address Safety Issues at All 
Levels of the Hierarchy 

Mine safety is a complex, multidetermined phe- 
nomenon. The attitudes and behaviors of the workers are 
important, but so are the attitudes and behaviors of man- 
agement. Incentive systems, working conditions, organi- 
zational culture, individual habits, and managerial prac- 
tices all influence safety. Each team addressed the 
question of what it could do to improve mine safety. Natu- 
rally the answers differed, but teams at all levels imple- 
mented specific actions to improve the safety record, and 
these actions had a cumulative, long-term effect on injury 
rates. 

Conduct the Program at a "Treatment" 

Mine and Designate a "Control" Mine 

to Receive No Treatment 

The OD program was given to the Lucky Friday Mine 
and withheld from the Star Mine, thereby creating an 
experimental-control group research design. This allowed 
effects due to the program to be inferred more easily. Se- 
lection of the Lucky Friday Mine to receive the treatment 
was done on a nonrandom basis. The Lucky Friday was 
considered the more difficult mine to work with because it 
had problems of low morale, a poor safety record, anticom- 
pany attitudes, and was a unionized mine. However, if the 
program were successful, the benefits would be greater 
because the Lucky Friday was a richer mine than the Star. 



CHRONOLOGY OF PROGRAM EVENTS 

The major program activities with supporting ration- 
ale are presented in chronological order. The Hecla pro- 
gram progressed through the following phases: entry, ori- 
entation, and diagnosis; designing the plan of action; 
implementing the action plan; consolidating and expand- 
ing the program accomplishments; and transferring the 
conduct of the program to company members. These 
phases and the actions taken to implement them are dis- 
cussed in the following sections. 



Entry, Orientation, and Diagnosis — 1979 

July 1979. — Hecla agreed to participate in the 
demonstration project, a memorandum of understanding 
was signed by the company and the consultants, and the 
program officially began. 

August -December 1979. — The consultants conducted 
over 400 interviews with more than 60 salaried employees 
to learn about the company, the industry, mine safety, and 
mine productivity. These interviews provided an orienta- 
tion for the consultants and a diagnosis of the organiza- 
tion's dynamics. 

November 1979. — The president asked the consultant 
to design a new performance appraisal system for all 
salaried employees. The consultant agreed to do so. Devel- 
opment of the new system allowed the consultants to 
demonstrate their usefulness to the company and show the 
employees how OD consultants work. First, the goals and 
guidelines for the new system were solicited from the se- 
nior executives. Next, actual performance dimensions and 
performance standards were obtained from three repre- 
sentative groups of employees, who would be rated on the 
new forms. Suggestions for improving the appraisal sys- 
tem itself were also solicited. The consultants then drafted 
three new appraisal forms, one for managers, one for 
professional-technical employees, and one for clerical em- 
ployees, which were submitted to the senior management 
team for its reactions and approval and to the representa- 
tive groups for their reactions. Everyone liked the new 
forms and the new system that they had helped to create. 
This was an early success for the OD program that had 
high visibility and widespread approval. 



141 



Proposal and Plan of Action — 1980 

January 1980. — A report summarizing the organiza- 
tional diagnosis and proposing several alternative ways to 
proceed was given to the president and senior manage- 
ment team. 

February 1980. — A meeting was held with the presi- 
dent and senior executives to decide on the strategy and 
implementation of the OD project. The proposal was re- 
viewed, the strengths and weaknesses of the company 
were discussed, and a plan of action was decided. The fol- 
lowing decisions were made: team building-problem solv- 
ing meetings would be the principal intervention used, the 
program would focus on the operations (production) func- 
tion in the company, the program would start at the top of 
the organization and would eventually involve the hourly 
employees, the target mine would be the Lucky Friday 
Mine, and mine safety would be addressed by teams at all 
levels of the organization. 

April 1980. — The new performance appraisal system 
was installed. All raters were given a one-half day train- 
ing session conducted by the consultants on how to use the 
new system and how to conduct performance appraisals. 
The training was well received; it yielded another early 
success for the program. 

Implementing the Action Plan — 1980-82 

June 1980. — The first team building meeting with 
the president and senior management team was held. This 
launched team building-problem solving meetings in the 
company. The procedure for team building meetings was 
simple and straightforward: prior to the first meeting ev- 
eryone was interviewed and asked to identify the 
strengths and weaknesses of the organization and the 
team. The interview results were reported to the group at 
the first meeting and the team was asked to prioritize the 
problem areas in order of importance. The prioritized list 
was then worked through, each problem was examined, 
and action plans were developed and implemented to solve 
the problems. 

August 1980. — The first team building meeting with 
the vice president of operations and the operations team 
was held. On this team were the vice president, three mine 
managers, the project engineer for the Silver Shaft (a new 
shaft at the Lucky Friday), and the assistant personnel 
director, who had corporate responsibility for mine safety. 

October 1980. — Team building with the Lucky Friday 
mine manager and mine top management team was 
begun. This team consisted of the mine manager, the mine 
superintendent, three production foremen, and support 
personnel from maintenance, safety, geology, engineering, 
accounting, and warehousing. 

The guiding strategy for 1981 was to continue every- 
thing already begun and concentrate on the Lucky Friday 
Mine. 

February 1981. — The first team building meeting 
with the Lucky Friday production team was held. This 
team included the mine manager, mine superintendent, 
mine foremen, shift bosses, the maintenance foreman, and 
the safety forman. Policies were developed and imple- 
mented that caused long-standing problems to disappear; 
agreements on goals, procedures, and mutual expectations 
were reached that caused better coordination and coopera- 
tion. Another important benefit was that the shift bosses 



came to realize that the company was interested in them, 
their problems, and their ideas. 

March 1981. — A 9- week strike occurred at the Lucky 
Friday Mine. The strike lasted from March 21 to May 23. 

April 1981. — Annual goal setting meetings with the 
vice president of exploration and the exploration depart- 
ment were begun. 

August 1981. — Team building meetings with four 
Lucky Friday production crews and their shift bosses were 
begun. Six 45-min meetings were held in 1981. Prior to to 
the meetings, the consultants explained the program to 
the top union officials at the mine, the president, 
secretary- treasurer, and safety committeeman. They were 
very supportive of the program and offered to explain and 
endorse it to the crews. They particularly liked the idea of 
initiating a constructive dialogue in which management 
would hear the views of the hourly employees. 

September 1981. — Intergroup team building meet- 
ings were held with opposite shift crews. These meetings 
were designed to increase communication, coordination, 
and cooperation between crews that worked the same level 
of the mine and same stopes (working places), but worked 
on different shifts. 

November 1981. — Team building meetings with the 
Lucky Friday maintenance crew and supervisors were 
begun. 

May 1982. — The Bureau of Mines demonstration proj- 
ect was completed. A final report to the Bureau evaluating 
the Hecla project concluded that the program probably 
improved mine safety but had no discernible effect on mine 
productivity. 

May 1982. — The president hired the consultant to 
continue the OD program and extend it to the rest of the 
company. 

Consolidating Achievements, Expanding the 

Program, and Transferring the Conduct of the 

Program to Company Members — 1982-85 

These phases continued the implementation of the ac- 
tion plan, but added three new emphases — making the 
team building meetings a permanent fixture in the com- 
pany, expanding the team building meetings to include 
other units, and training company members to conduct the 
program. Team building meetings have become a fact of 
life at Hecla: the senior management team holds annual 
2-day meetings, the operations team holds two l 1 /2-day 
meetings per year, and the Lucky Friday Mine top man- 
agement team and mine production team hold quarterly 
meetings. Meetings with the crews conducted by the con- 
sultant have not been held since early 1982, but problem 
solving meetings with the hourly work force conducted by 
Lucky Friday supervisors and managers are routinely 
held. Team building meetings have been expanded to in- 
clude all the major functional units of the company. 

June 1982. — Behavior modeling skills training was 
initiated for the Lucky Friday mine superintendent, mine 
foremen, and safety foreman. Behavior modeling is a 
training technique that teaches supervisors how to become 
more effective at handling interpersonal problem situa- 
tions. 

June 1982. — Mining operations at the Star Mine were 
discontinued for economic reasons. 

November 1982. — Team building meetings, con- 
ducted jointly by the personnel director and the consul- 
tant, were begun at the Knob Hill gold mine in Republic, 



142 



WA. The teaching of OD consultant skills to the personnel 
director was accomplished using an apprenticeship ap- 
proach, in which the personnel director was a coconsultant 
on the project. 

May 1983. — A 2-day annual retreat for the president 
and senior management team was inaugurated to replace 
the previous team building meetings. 

June 1983. — Team building meetings with the corpo- 
rate secretaries were held. Discussions and decisions cen- 
tered on secretarial policies and procedures. 

September 1983. — A new mine manager was ap- 
pointed at the Lucky Friday Mine. To orient him to the 
team building process and to get the process started on a 
sound footing, a new series of diagnostic interviews was 
conducted, the results of which formed the agenda for the 
next several meetings. These meetings were conducted 
jointly by the director of training and the consultant, using 
an apprenticeship approach. 

February 1984. — Team building meetings with the 
technical services department (the corporate engineering 
department), conducted by the director of training and the 
consultant, were begun. 

November 1984. — Team building meetings with the 
corporate administrative services group, conducted by the 
director of training and the consultant, were begun. Two 
vice presidents and their teams attended these meetings; 
together they constitute all the administrative support 
functions in the company — legal, accounting, data proc- 
essing, payroll, etc. 

January 1985. — A new program, team problem solv- 
ing (TPS), was initiated by the director of training and 
consultant. TPS had two broad objectives: teaching team 
problem solving skills to line managers and developing 



additional team building facilitators in the company. The 
first group to get TPS was the Lucky Friday mine manager 
and mine top management team. Later the program in- 
cluded the shift bosses at the Lucky Friday, and it then 
was expanded to other company units. Seven midlevel 
managers were trained to become internal OD consul- 
tants, using a classroom teaching and apprenticeship for- 
mat. 

March 1985. — Team building meetings, conducted 
by the personnel manager and consultant, were begun 
with the mine manager and management team at the Es- 
calante Mine near Cedar City, UT. 

Summary 

Organization development techniques such as coach- 
ing and counseling, goal setting, team building-problem 
solving, intergroup problem solving, and role clarification 
are now normal, routine modes of operation at Hecla Min- 
ing Co. Teams at all levels periodically meet to discuss two 
questions: How are we doing? How can we do better? Seek- 
ing answers to these two questions is the essence of team 
building-problem solving, and, in fact, OD. These meet- 
ings are usually conducted by the managers themselves or 
by the managers with assistance from an internal OD 
consultant. 

The strategy, rationale, and activities of the Hecla 
program presented in this section show how the program 
was designed and implemented. Team building was an 
excellent vehicle for conducting the program. Institution- 
alizing team problem solving skills by training line man- 
agers and internal consultants ensured that the program 
would be continued. 



RESULTS 



This section examines the effects of the OD program 
using safety and productivity data from 1979 through 
June 3 1985. Did the program do any good? That is the 
question to be answered. Nine performance indicators 
were analyzed, one for mine safety and eight for mine 
productivity. Program effects were estimated by examin- 
ing preprogram and postprogram measures at the Lucky 
Friday Mine (a before-and-after comparison), and by ex- 
amining results at the experimental mine and comparison 
mine. These analyses permit inferences to be made about 
possible program effects. 

The years 1979 and 1980 were treated as the prepro- 
gram years; 1981 and following were the postprogram 
years. The OD program at the Lucky Friday Mine actually 
began in mid-1981, but using the base period of 1979 and 
1980 to approximate the before condition is satisfactory for 
this paper. Data were collected at the Lucky Friday Mine 
through June 1985. 

In addition, t- tests were calculated on Lucky Friday 
data to determine the statistical significance of differences 
before and after the OD program. The t-tests were gener- 
ated using quarterly averages. There were nine prepro- 
gram quarters — from January 1979 through the first 
quarter of 1981; there were 16 postprogram quarters — 
from the third quarter of 1981 through the second quarter 
of 1985. Data from the second quarter of 1981, during 



which a 9-week strike occurred, were not used in the t-test 
analyses. 

It is important to specify the date of the onset of the 
OD program. Team building meetings with the mine man- 
ager and mine top management team were initiated in 
October 1980. Team building meetings with the mine 
manager and mine production team began in February 
1981. The strike occurred from March 21 to May 23, 1981. 
Team building meetings with the crews occurred in Au- 
gust, September, and October of 1981. It seems reasonable 
to fix the beginning of the program as the end of the second 
quarter of 1981. At that time several meetings had been 
held with the mine top management team and the mine 
production team, the strike was over, and operations at the 
mine were returning to normal. The preprogram period is 
up to the strike; the postprogram period is after the strike, 
beginning in July 1981. 



DESCRIPTION OF MEASURES 

Data to evaluate the program were obtained from 
company records. The company routinely monitors safety 
and productivity by means of standard indicators used 
throughout the industry. The nine indicators used in the 
present analyses are described in the following sections. 



143 



Lost-Time Injury Incidence Rate 

The standard measure of mine safety is the lost-time 
injury incidence rate obtained by the formula, lost-time 
injuries x 200,000 /employee- hours. 

Worker Hours of Exposure 

Data for this measure were taken from Hecla records 
and Mine Safety and Health Aministration (MSHA) 
records. 

Tons Per Day 

This is the number of tons of ore removed from the 
mine in a single working day. Tons per day is an absolute 
number, not an input-output ratio. It will vary both as a 
function of productivity and as a function of managerial 
decisions. For example, during the period under investiga- 
tion, management deliberately increased the output of the 
mine from 750 st/d to 1,000 st/d. 



Ounces of Silver Per Worker Shift— All Labor 

This is the total amount of silver produced by the total 
worker shifts required to obtain it. This measure shows 
the output of salable product per unit of labor required to 
produce it. 

Cost Per Ton 

This is the production costs in dollars for each ton of 
ore removed from the mine, a standard cost meaure in 
mining. Costs are proprietary information, so the present 
analyses use percentages in the presentation of results. 

Cost Per Ounce 

This is the production costs in dollars for each ounce 
of silver produced, a standard indicator of cost per unit of 
salable product. The present analyses use percentages in 
the presentation of results. 



Total Ounces of Silver 

This is the number of ounces of silver produced in a 
given time period. Silver is the main salable product of the 
Lucky Friday Mine. Total ounces of silver is the number of 
units of product available to be sold. This is an absolute 
number, not an input-output ratio. 

Tons Per Worker Shift-Stoping 

This is the number of tons of ore removed from the 
mine in a working day divided by the number of shifts 
worked by the stope miners who produced the ore. It is a 
standard productivity measure in the industry, and is the 
purest measure of productivity of the stope miners, the 
people who break the rock. 

Tons Per Worker Shift-All Labor 

This is the number of tons of ore removed from the 
mine in a working day divided by the total number of 
worker shifts worked at the mine. It includes the shifts of 
stope miners and all support personnel, both underground 
and on the surface. This measure will vary both as a func- 
tion of changes in productivity and as a result of manage- 
ment's effectiveness in utilizing mine personnel. For ex- 
ample, if the number of tons of ore increases, but the 
number of all labor worker shifts increases even more, the 
net result is a decrease in this indicator. 

Grade of Silver, or Ounces per Ton 

This is the number of ounces of silver per ton of ore 
removed from the mine. This standard measure of produc- 
tion quality is a function of several variables: good mining 
practices by the stope miners, geological conditions, and 
managerial decisions. The miners can influence grade by 
carefully mining on the vein and not diluting the ore with 
waste rock. Geological conditions dictate the amount of 
silver available to be mined. Managerial decisions influ- 
ence grade primarily through the amount of development 
work going on in the mine — if there is extensive develop- 
ment work, more waste rock will be mixed with the ore 
causing grade to decline. 



BEFORE-AND-AFTER RESULTS AT 
THE LUCKY FRIDAY MINE 

The results for each performance measure at the 
Lucky Friday Mine are presented and discussed in this 
section. For comparison purposes, the years 1979 and 1980 
are treated as before and the years 1981 though June 1985 
are treated as after in the analyses. Table 1 shows annual 
averages for the safety and production measures. Table 2 
presents the same data transformed into percentage 
changes from the base period 1979-80, and in addition 
shows cost information in percentage changes from the 
base period. 

Lost-Time Injuries 

The data in tables 1 and 2 show a 44.1 pet decrease in 
lost-time injuries in 1981, the year the OD program was 
initiated. It is reasonable to assume that some of this im- 
provement was due to the program. Thus the primary 
question the Bureau wanted answered — Can OD tech- 
niques improve mine safety? — is answered: Yes, they can. 

In addition, the gains in mine safety were sustained 
over time. The injury rate increased somewhat in 1982, 
decreased again in 1983, and increased in 1984. But the 
rates remained below the base period, averaging a 38.2 pet 
decrease for the 4-yr period 1981 through 1984. In 1985, 
there was a dramatic drop in injuries — a 78.7 pet improve- 
ment over the base period. The employees at the Lucky 

Table 1 . — Annual averages of safety and production meas- 
ures at the Lucky Friday Mine, 1979 through June 1985 



Measure 



Safety: Lost-time injury 

incidence rate 

Production: 

Ore st/d . . 

Silver 10 6 oz 

Productivity, st/worker shift: 

Stoping 

All labor 

Grade oz/st . . 

Productivity 

oz/worker shift . . 



1979 



22.92 

704 
2.884 

11.23 

2.98 

16.67 

49.44 



1980 



23.04 

737 
3.118 

11.46 

2.90 

16.78 

48.78 



1981 



12.85 

716 
2.253 

11.19 

2.64 

15.14 

40.53 



1982 



15.62 

837 
3.858 

10.84 

3.16 

18.30 

58.63 



1983 



13.27 

1,017 
5.145 

13.39 

3.40 

20.42 

69.27 



1984 



15.11 

1,017 
4.786 

15.55 

3.24 

19.03 

61.64 



1985 



4.9 

1,100 
5.004 

17.51 

3.90 

18.28 

72.28 



144 



Table 2. — Comparison of safety, production, and cost 

measures at the Lucky Friday Mine, 1981 

through June 1985, percent 

[Base (1979-80) = 100 pet] 



Measure 

Safety: Lost-time injury rate . . 
Production: 

Short tons per day 

Total ounces of silver 

Short tons per worker shift: 

Stoping 

All labor 

Ounces per short ton 

Ounces per worker shift, all 

labor 

Cost: 
Dollars per short ton: 

Actual 

Inflation adjusted 

Dollars per ounce: 

Actual 

Inflation adjusted 



1981 



55.9 

99 
75.1 

98.6 
89.7 
90.5 

82.5 



143 
123 

154.4 
133.7 



1982 



67.9 

116.2 
128.6 

95.5 
107.5 
109.4 

114.6 



111.2 
89.5 

100 

80.5 



1983 



57.7 

141 
171.4 

118 

115.6 

122.1 

141 



106.3 
82.9 

87.4 
68 



1984 



65.7 

141 
159.5 

137 

110.2 

113.8 

125.5 



131.9 
98.7 

116.6 
87.3 



1985 



21.3 

152.7 
166.7 

154.3 
132.6 
109.3 

147 



123.2 
89.9 

108 
79 



Friday Mine went 88 working days without a lost-time 
injury, which was an all-time record. 

It appears that the results show two major discontinu- 
ities: the first occurred in 1981 and continued through 
1984, and the second occurred in 1985. Both the 1981 re- 
sults and the 1985 results mark significant departures 
from previous periods. A t-test showed that the lost-time 
injury incidence rate was significantly lower after the OD 
program: t(23) = 2.60, p <0.01 for one-tailed test. 



Tons Per Day 

The data for tons per day show that the quantity of ore 
removed per day decreased 1 pet in 1981, then rose from 
1982 through 1985. A gain of 16.2 pet was achieved in 
1982, followed by gains of 41 pet in both 1983 and 1984, 
and 52.7 pet in 1985. These increases in total mine output 
were due to a combination of causal factors: management 
decisions to increase production, more employees on the 
payroll, and greater productivity. The amount of contribu- 
tion of each of these factors (and the OD program) cannot 
be determined. What is clear is that production of ore was 
increased from approximately 700 st/d in 1979 to 1,100 st/d 
in 1985. A t-test for tons per day before and after the OD 
program showed the differences were significant: 
t(23) = 5.44, p <0.0005 for a one-tailed test. 



Total Ounces of Silver 

This is an absolute number that depicts how much 
salable product is generated in a given time period. Total 
ounces produced depends on a number of factors such as 
managerial decisions to increase the tons of ore mined, 
mining more or less rich parts of the mine, and productiv- 
ity of individuals. Total silver output decreased by 25 pet 
in 1981 compared to the base period, but increased sub- 
stantially in the following year — up 28.6 pet in 1982, up 
71.4 pet in 1983, up 59.5 pet in 1984, and up 66.7 pet in 
1985. These are substantial increases compared to the pre- 
program levels. The differences in silver production before 
and after the OD program were statistically significant: 
t(23) = 1.793, p <0.05 for a one-tailed test. 



Tons Per Worker Shift— Stoping 

The ore is produced by miners who work in stopes 
drilling, blasting, and mucking the ore. The best measure 
of stope miner productivity is the total number of tons of 
ore produced divided by the total number of worker shifts 
worked by stope miners. Annual averages for this measure 
are shown in table 1 and percentage changes are shown in 
table 2. 

These data show a decrease of 1.4 pet in 1981 and a 
decrease of 4.5 pet in 1982, compared to the base years of 
1979 and 1980. At that point, however, stope miner pro- 
ductivity started to increase: up 18 pet in 1983, up 37 pet 
in 1984, and up 54.3 pet in 1985. It is important to note 
that the impact of the OD program was not immediately 
reflected in improvements in stope miner productivity; 
rather, there was a delay of 1 yr before increases began to 
be seen. One explanation for this was that the company 
and the miners were engaged in a dispute over the admin- 
istration of the contract system in late 1981 and 1982, with 
a slowdown staged by the miners in 1982. The issues were 
resolved in late 1982, and productivity started on a steady 
rise. A t-test for tons per worker shift — stoping before and 
after the OD program showed the differences were signifi- 
cant: t(23) = 2.49, p <0.025 for a one-tailed test. 



Tons Per Worker Shfit— All Labor 

A good measure of overall mine efficiency is the total 
output of ore divided by the number of worker shifts 
worked by all persons at the mine. This measure reflects 
both the productivity of individual stope miners and the 
ability of management to utilize efficiently the total 
human resources at the mine. 

Tons per worker shift — all labor was down 10.3 pet in 
1981, up 7.5 pet in 1982, up 15.6 pet in 1983, up 10.2 pet 
in 1984, and up 32.6 pet in 1985 compared to the base 
period. Productivity started to improve in the third quar- 
ter of 1981; there was no delayed effect as seen for tons per 
worker shift — stoping. A t-test showed that the pre- and 
post-intervention differences were statistically signifi- 
cant: t(23) = 2.96, p <0.005 for a one-tailed test. 



Grade of Silver, or Ounces Per Ton 

The grade of silver, measured in ounces of silver per 
ton of ore mined, is an indicator of production quality. 
Careful mining practices by the stope miners can increase 
the ounces per ton of ore. Additional factors contributing 
to grade are geological conditions and the amount of devel- 
opment activity. 

Compared to the base period of 1979-80, grade de- 
creased by 9.5 pet in 1981, but increased in the years 
following: up 9.4 pet in 1982, up 22.1 pet in 1983, up 13.8 
pet in 1984, and up 9.3 pet in 1985. This is an important 
efficiency and effectiveness indicator, because keeping 
grade as high as possible means that fewer tons of waste 
rock have to be hoisted from the mine and processed 
through the mill. The increase in grade after the OD pro- 
gram was statistically significant: t(23) = 3.68, p <0.005 
for a one-tailed test. 



145 



Ounces of Silver Per Worker Shift — All Labor 

A meaure that reflects both managerial effectiveness 
in utilization of human resources and individual produc- 
tivity is the ratio showing the total ounces of silver pro- 
duced divided by the total worker shifts worked to produce 
them, ounces per worker shift — all labor. 

Compared to the base period, ounces per worker 
shift — all labor was down 17.5 pet in 1981, up 11.5 pet in 
1982, up 41 pet in 1983, up 25.5 pet in 1984, and up 47 pet 
in 1985. This is a key efficiency measure, amount of sal- 
able product per unit of labor, and it shows substantial 
improvement from 1982 forward. The difference between 
preprogram and postprogram scores is statistically signif- 
icant: t(23) = 3.59, p <0.0005 for a one-tailed test. 



Cost Per Ton and Cost Per Ounce 

Two standard cost indicators are production costs 
measured by dollars per ton of ore mined and production 
costs measured by dollars per ounce of silver produced. 
Cost information is proprietary information for most min- 
ing companies, therefore the present analyses use per- 
centage changes only. Analysis showed how well costs 
were being managed before and after the OD program. 
Both actual dollar costs and constant (inflation-adjusted) 
costs were examined. Table 2 shows annual cost per ton 
data by year. 

Compared to the base period, actual production costs 
per ton of ore mined were up 43 pet in 1981, up 11.2 pet in 
1982, up 6.3 pet in 1983, up 31.9 pet in 1984, and up 23.2 
pet in 1985. The sharp increase in costs in 1981 was 
brought down in 1982 and 1983, but costs rose again in 
1984 and 1985. A review of inflation-adjusted costs per ton 
shows that costs were up 23 pet in 1981, and then lower 
than the base period for the following 4-yr period: down 
10.5 pet in 1982, down 17.1 pet in 1983, down 1.3 pet in 
1984, and down 10.1 pet in 1985. These data show that 
costs were being controlled quite well in the postprogram 
period. 

Cost per ounce reflects the costs involved in producing 
a unit of salable product. As shown in table 2, the cost per 
ounce in actual dollars rose 55.4 pet in 1981, then returned 
to the level of the base period in 1982. In 1983 costs showed 
a decrease of 16.6 pet but then were up 16.6 pet in 1984 and 
up 8 pet in 1985. In constant dollars, cost per ounce was up 



33.7 pet in 1981, but down 19.5 pet in 1982, down 32 pet in 
1983, down 12.7 pet in 1984, and down 21 pet in 1985. 
These figures show that management was doing a good job 
controlling costs except in the year 1981, the year of the 
strike and its settlement. 

Summary and a Caveat 

The data presented show a great deal of variability, 
but the trends are positive on all measures at the Lucky 
Friday Mine from pre- to post-intervention. Comparing 
the first 6 months of 1985 to the base period of 1979 and 
1980 yields the following results: 

Lost-time injury incidence rate — down 78.7 pet. 

Total tons of ore produced per day — up 54.7 pet. 

Tons per worker shift — stoping — up 54.8 pet. 

Tons per worker shift — all labor — up 33 pet. 

Total ounces of silver — up 72.1 pet. 

Grade of silver (ounces per ton) — up 10.4 pet. 

Ounces per worker shift — all labor — up 47 pet. 

Cost per ton — actual dollars — up 23.2 pet. 

Cost per ton — inflation-adjusted dollars — down 10.1 pet. 

Cost per ounce — actual dollars — up 8 pet. 

Cost per ounce — inflation adjusted dollars — down 21 
pet. 

There is significant improvement on all indicators — 
safety, quantity of production, quality of production, and 
costs. The year 1981 marked a turning point at the Lucky 
Friday. A 9-week strike occurred in March, April, and 
May; the OD program began in earnest in mid- 1981. Lost- 
time injuries decreased dramatically in 1981 and have 
remained below preprogram levels ever since. Productiv- 
ity measures reached their lowest point in 1981 and have 
risen substantially since then. All t-test comparisons 
showed that the differences between preprogram and post- 
program scores were significant. Clearly the mine is func- 
tioning better now than it was in 1979 and 1980. 

But a caveat is appropriate here: it would be wrong to 
attribute all or even most of these positive changes to the 
OD program — so many different events were occurring 
over such a long period of time that precise identification 
of the causal factors can not be made. It is reasonable to 
conclude that the OD program had a positive impact on 
safety and productivity at the Lucky Friday Mine; but it is 
also reasonable to conclude that a number of non-program- 
related factors did too. Some of these other possible causes 
are discussed in the "Discussion and Conclusions" section. 



COMPARISONS BETWEEN THE EXPERIMENTAL AND CONTROL MINES 



The Lucky Friday Mine received the treatment as the 
experimental mine, while the Star Mine received no treat- 
ment as a comparison mine. Unfortunately the Star Mine 
was closed in June 1982, resulting in the loss of the com- 
parison mine for long-term comparisons. Short-term 
analyses were possible, however, and they are reported in 
this section. 

Two major evaluation problems resulted from the loss 
of the control mine. The first problem was the loss of the 
ability to make long-term comparisons between the two 
mines. The Lucky Friday analyses in the previous section 
showed that the data were highly variable, changes 
showed up at different times, and new trends were identi- 
fied only after several years of observations. Although the 



data from the Star Mine showed gains, it is not possible to 
know whether these reflected permanent trends. 

The second problem was that the Star data were dis- 
torted by the shutdown dynamics. Many people in Hecla 
were doing their best to keep the Star from closing. The 
employees at the mine worked harder and smarter in order 
to save their jobs. Managers and engineers looked for ways 
to make the mine more profitable. Mining in less prof- 
itable stopes (working places) was discontinued; more 
profitable stopes were double shifted, that is, were mined 
on both day shift and swing shift. Twenty percent of the 
work force was laid off on January 1, 1982. Persons with 
greater seniority and experience were retained after the 
layoff. Finally, 5,000 st of previously broken ore that was 



146 



stored in the mine was removed in the last months of 
operation. The point is that the shutdown dynamics cre- 
ated distortions in the performance measures and con- 
founded the true changes that occurred with the changes 
because of the mine closure procedures. With these 
caveats and complications in mind, the comparative data 
between the experimental and comparison mines are ex- 
amined. Comparisons were made on four indicators: lost- 
time injuries, tons per worker shift — stoping, tons per 
worker shift — all labor, and cost per ton. Analyses used 
data up to June 1982 at the Star Mine. 

Lost-time injury incidence rates at the Lucky Friday 
and Star Mines (table 3) show the annual lost-time injury 
incidence rates and percentage changes at the Lucky Fri- 
day and Star Mines compared to the base years of 1979 and 
1980. The Star Mine injury rates were lower than those at 
the Lucky Friday in 1979 and 1980. In 1981, the injury 
rate at the Lucky Friday decreased by 44 pet compared to 
a decrease of 8 pet at the Star. This may be evidence that 
the OD program had a positive influence on safety at the 
Lucky Friday, since there was a large rate decrease at the 
experimental mine and a small rate decrease at the control 
mine. In 1982, however, the injury rate was down 32 pet at 
the Lucky Friday and down 37 pet at the Star, compared 
to the base period. The decrease at the Lucky Friday was 
expected but the sizable decrease at the Star was not. The 
causes of the decrease in injury rates at the Star Mine are 
not known. It is also unclear whether the decrease signi- 
fied a new trend for injuries at the mine. 

TONS PER WORKER SHIFT— STOPING 

Annual averages for tons per worker shift — stoping at 
the two mines are shown in table 3. Compared to produc- 
tivity at the Lucky Friday, productivity at the Star Mine 
was higher during the base period and increased by 13.4 
pet in 1981 and by 22 pet in 1982. Productivity at the 
Lucky Friday decreased in both these years compared to 
the base period. These gains at the Star Mine were sub- 
stantial. Unfortunately, the shutdown dynamics made it 
impossible to determine the true significance of these pos- 
itive results. 



TONS PER WORKER SHIFT— ALL LABOR AT 
THE LUCKY FRIDAY AND STAR MINES 



Table 3. — Annual performance averages at the Star Mine 
and Lucky Friday Mine for safety, production, and costs 

(Comparison of 1981 and 1982 with 1979-80 base) 





1979 


1980 


1981 


19821 


Change, pet 


Measure 


1981 


1982 


Safety, lost-time injury incident 
rate: 

Star 

Lucky Friday 


15.2 
22.9 

16.7 
11.23 

3.5 
2.98 

W 
W 

W 
W 


15.2 
23.0 

15.4 
11.46 

3.3 
2.90 

W 
W 

W 
W 


14.0 
12.85 

18.2 
11.19 

3.7 
2.64 

W 
W 

W 
W 


9.6 

15.6 

19.6 
10.84 

3.9 

3.16 

W 
W 

W 
W 


92 
55.9 

113.4 
98.6 

108.8 
89.7 

107.7 
143 

92.4 
123 


63 

67.9 


Production, st/worker shift: 
Stoping: 

Star 

Lucky Friday 


122 

95.5 


All labor: 

Star 

Lucky Friday 


114.7 
107.5 


Cost, dollars per short ton: 
Actual: 

Star 

Lucky Friday 


105.1 
111.2 


Inflation adjusted: 

Star 

Lucky Friday 


84.4 
89.5 










W Withheld 1 Star Mine data are from January to June only. 

1982 at the Lucky Friday. These gains at the Star Mine 
are impressive, but the causes of the improvements are 
unknown. 

COST PER TON AT THE LUCKY FRIDAY AND 
STAR MINES 

Table 3 shows cost figures in percentages at the two 
mines compared to the base period of 1979 and 1980. Both 
actual dollar costs and inflation-adjusted or constant dol- 
lar costs are shown. The Star Mine showed actual cost 
increases of 7.7 pet in 1981 and 5.1 pet in 1982, but showed 
decreases of 7.6 pet in 1981 and 15.6 pet in 1982 in con- 
stant dollars. Cost per ton at the Lucky Friday Mine 
jumped 43 pet in actual dollars and 23 pet in constant 
dollars in 1981, the year of the strike and its settlement, 
and were up 11.2 pet in actual dollars and down 10.5 pet in 
constant dollars in 1982. Again there is evidence of signif- 
icant improvement at the Star Mine during 1981 and 
1982, the causes of which can not be precisely identified. 

SUMMARY 



Table 3 shows annual averages for tons per worker 
shift — all labor at the two mines. This measure reflects 
both productivity and management's ability to utilize the 
mine workforce in an efficient manner. Again productivity 
at the Star Mine was higher than that at the Lucky Friday 
during the base period. Productivity increased at the Star 
by 8.8 pet in 1981 and 14.7 pet in 1982, compared to a 
decrease of 10.3 pet in 1981 and an increase of 7.5 pet in 



All the indicators showed improvement at the Star 
Mine, the comparison mine, in 1981 and up to the mine's 
closure in June 1982. Whether the trends were permanent 
and what the causes of the gains were can not be known 
from these data, because the impact of the shutdown dy- 
namics could not be isolated and specified. The gains at the 
Star Mine did not achieve the magnitude of the gains at 
the Lucky Friday Mine found in 1985, however. 



147 



DISCUSSION AND CONCLUSIONS 



The OD program has been described and the results 
reported. In this section, several conclusions are advanced, 
concurrent events that may have caused the results are 
examined, ingredients for success are identified, and im- 
plications of this research for the mining industry are pro- 
posed. (Although this research was conducted in a silver 
mining company, it is probable that the results apply 
equally well to the entire mining industry, both metal- 
nonmetal and coal.) 



CONCLUSIONS 

Important positive changes occurred at the Lucky Fri- 
day Mine and Hecla Mining Co. since 1979 on almost 
every performance indicator. Hecla is the premier silver 
mining company in the United States. Hecla's top man- 
agement team is very highly regarded; for 5 of the past 6 
yr, The Wall Street Transcript has named Mr. Griffith the 
top silver company chief executive in the Nation. Safety 
and productivity have improved dramatically at the Lucky 
Friday since 1981. 

It is reasonable to believe that the OD program was a 
positive force at Hecla. It was not the only positive force or 
even the most important positive force, but it probably 
contributed to better organizational effectiveness, espe- 
cially at the Lucky Friday Mine. The first conclusion is 
that OD techniques can improve mine safety and produc- 
tivity in hard-rock mining. The data strongly support such 
a conclusion. 

A second conclusion is that the OD approach is accept- 
able to mining company executives and employees. The 
essence of the OD approach is that an outsider, a behav- 
ioral science consultant, collaborates with the organiza- 
tion's members, helping them to concentrate their exper- 
tise on solving their most important problems. The 
consultant provides a method; the organization members 
provide the effort, energy, and expertise. The method must 
be compatible with common sense, good management 
practices, and the culture of the organization. OD tech- 
niques, especially team building, are natural, nonthreat- 
ening, effective activities that facilitate problem solving. 
The OD approach uses a rational, data-based foundation, 
encourages participation and involvement by the key per- 
sons, focuses on task accomplishment, and deals witb real 
issues not hypothetical cases. This combination appealed 
to Hecla's employees; it would likely appeal to executives 
and employees of other mining companies. 

A third conclusion, evident in the results at the Lucky 
Friday Mine, is that mine safety and productivity can be 
improved simultaneously — they are not mutally exclusive 
outcomes. On reflection this conclusion should not be sur- 
prising: good safety practices and high productivity both 
result from good management practices and good em- 
ployee attitudes. Any program that improves managerial 
skills and employee involvement should improve safety 
and productivity together. 

Fourth, team building-problem solving meetings are a 
powerful technique for increasing organizational effec- 
tiveness. This is true for several reasons. Team building 
meetings address and solve high-priority problems facing 
the team; this in itself causes better functioning. In addi- 
tion, team building causes a shift toward a more problem- 
and task-oriented focus. This shift serves to energize and 



empower people. Individuals and teams become more com- 
petent and able to face other demands placed upon them at 
work. Finally, team building is not very different from 
what effective leaders and teams do naturally — take a 
systematic look at how they are getting the job done in 
order to find ways to do it better. 

CONCURRENT EVENTS AND RIVAL 
EXPLANATIONS 

Attributing causality for the positive results achieved 
at the Lucky Friday Mine is difficult. The OD program was 
probably one positive factor in producing the improve- 
ments. But there were other factors and events that (1) 
produced positive results and (2) can be considered rival 
explanations as the causes producing the changes. Be- 
cause this was a global intervention extending over 6 yr, 
many rival explanatory events were happening concur- 
rently with the OD program. Several rival causal factors 
are discussed here. 

Important management changes occurred coincident 
with the OD program. William Griffith was appointed 
president and chief executive officer of the company in 
May 1979. He has exerted strong influence on every aspect 
of the company, including promoting mine safety and pro- 
ductivity. A new vice president of operations was also ap- 
pointed in May 1979; he was experienced and knowledge- 
able and empbasized safety and productivity. A new mine 
manager was appointed at the Lucky Friday in 1980, and 
he served in that position until September 1983. The mine 
was turned around during his tenure as mine manager. 
His leadership and the new policies and procedures ini- 
tiated by him were possible causes of the improvements at 
the mine. The mine manager who took over in 1983 
showed strong, innovative leadership. It is likely that all 
these management changes were significant, positive 
forces contributing to the improvements that were 
achieved. 

Several mine policy changes probably played causal 
roles in increased performance. In 1982, a minable width 
policy was introduced that specified how wide on the vein 
stope miners could mine and still be paid for the broken 
rock. The intent and effect of this policy was to reduce the 
amount of waste rock being mined and to have the miners 
only extract ore-bearing rock. This policy probably af- 
fected grade, total ounces of silver, and ounces per worker 
shift — all in a positive manner. In 1983, a new contract 
incentive system was tested and then implemented 
minewide. This incentive system improved both the quan- 
tity and quality of ore mined, was perceived as more fair 
than the previous system, and increased the amount of 
money the stope miners could make. This new system 
probably increased productivity. In 1985, the mine man- 
ager negotiated individual performance contracts with all 
the shift bosses. These contracts amounted to goal setting 
for each first-line supervisor for costs, safety, and produc- 
tion quantity and quality. Goal setting is a proven way to 
increase performance. 

The year 1982 saw the closure of several large mines 
in the Coeur d'Alene district; metal prices were very low; 
many miners were looking for work. These conditions may 
have influenced performance at the Lucky Friday and Star 
Mines. 



148 



These concurrent events can be considered rival ex- 
planations for the improvements at the Lucky Friday 
Mine instead of the OD program. The nature of the data is 
such that the effects of these specific events can not be 
isolated. It is likely that all these factors (and more) were 
related to the results obtained. 



INGREDIENTS FOR SUCCESS IN THE PROGRAM 

The OD program was successful in two ways: it was 
well received by the organization, running its planned 
course with no disruptions; and it produced good results. 
The second outcome was made possible by the first. An 
assessment of the ingredients for success reveals the con- 
ditions under which OD programs might be successfully 
implemented in other hard-rock mining companies. 

One of the most important factors for success was the 
support given by Hecla's chief executive. Mr. Griffith in- 
sisted that the program be well conducted, be good for the 
organization, and be seen as useful by company members. 
As positive reports about the program accumulated, Mr. 
Griffith used the force of his position and personality to 
promote the program. When he started team building with 
himself and the senior management team, that sent a 
clear signal to the rest of the organization that the consul- 
tant and the program were being taken seriously. He 
showed his strong support again when the company as- 
sumed sponsorship of the program in June 1982, and it 
was at his direction that the program was institutional- 
ized. 

Another success factor was the support given to the 
program by the original Lucky Friday mine manager. 
New to the job, he welcomed the program as a means of 
accomplishing his objectives. Team building proved to be 
an excellent mechanism for ensuring communication, co- 
operation, and coordination with the managerial group at 
the mine. Mine policies and procedures were analyzed in 
team building meetings and reaffirmed, modified, or cre- 
ated as needed. As progress was made on chronic prob- 
lems, the mine manager and the entire managerial team 
became champions of the program. The mine manager's 
successor in 1983 was equally supportive of the OD effort; 
he expanded the program substantially, spearheaded the 
institutionalization process, and initiated many manage- 
rial improvements. 

The overall program strategy was a good one. Team 
building-problem solving meetings proved to be a good 



mechanism for bringing about change at Hecla. Starting 
at the top of the organization and working down the hier- 
archy was a sound approach. Focusing on real problems 
and opportunities, and translating words into action steps 
made team building meetings vital, rewarding, and fun. 

Several early successes helped legitimatize and ener- 
gize the program for company members. The new perform- 
ance appraisal system demonstrated the OD approach and 
resulted in an immediate useful product. The diagnostic- 
orientation interviews created high visibility and showed 
that the consultants were genuinely interested in helping 
the organization. Quick solutions to several long-standing 
problems at the Lucky Friday Mine created a sense of 
momentum and accomplishment for the mine manage- 
ment team. Early successes served as great testimonials 
for the OD program. 

Important developments in the past 2 yr that helped 
the success of the program included training company 
members to be internal OD consultants, and training line 
managers in team problem solving skills. Starting with 
the personnel manager and the director of training, the 
internal consultant group has been expanded to include a 
total of nine people. The facilitator cadre at Hecla is a 
potent force for success and for keeping the program vi- 
able. 



IMPLICATIONS FOR THE MINING INDUSTRY 

OD is a process for improving managerial practices 
and organizational dynamics toward the goal of improving 
organizational effectiveness. The Hecla project showed 
that OD can work in mining companies and that OD can 
improve mine safety and productivity. 

This demonstration project clarified something most 
people already know but often forget: mine safety and 
productivity are as much human and social results as they 
are engineering and technology results. Remove the 
personnel-created barriers to safety and productivity and 
positive, permanent improvements will be forthcoming. 
OD programs systematically analyze and overcome barri- 
ers to effectiveness, efficiency, and satisfaction in organi- 
zations. The implications for the mining industry are that 
programs focusing on the human side of performance are 
available; these programs can produce bottom-line bene- 
fits, and mining executives can evaluate these programs to 
see if any are appropriate for their companies. 



REFERENCES 



1. Trist, E. L., G. I. Sussman, and G. R. Brown. Experiment in 
Autonomous Working in An American Underground Coal Mine. 
Human Relations, v. 30, 1977, pp. 201-236. 

2. Goodman, P. S. Assessing Organizational Change: Rushton 
Quality of Work Experiment. Wiley-Interscience, 1979, 391 pp. 



3. Gavin, J. F., and R. E. Kelley. Psychological Climate and 
Reported Well-Being of Underground Miners: An Exploratory 
Study. Human Relations, v. 31, 1978, pp. 567-581. 

4. Beckhard, R. Organization Development: Strategies and 
Models. Addison- Wesley, 1969, 119 pp. 



149 



STRUCTURED MANAGEMENT TRAINING IN UNDERGROUND 
MINING— FIVE YEARS LATER 



By Fred E. Fiedler 1 



ABSTRACT 



A demonstration project in an underground trona mine showed that structured 
leadership training, consisting of leader match and behavior modeling, led to increased 
mine safety and productivity, with nearly undiminished effects over a 5-yr period. The 
training was highly cost effective and has considerable promise for widespread imple- 
mentation. 



INTRODUCTION 



A principal mission of the Bureau of Mines is the 
development of a safer and more productive work environ- 
ment. But despite extensive Federal and State regula- 
tions, mandated safety training and improvements in 
safety devices and mining techniques, underground min- 
ing is likely to remain one of the more hazardous occupa- 
tions. In its continuing effort to improve mine safety, the 
Bureau conducted a 3-yr demonstration project, 1979 to 
1982 (1 ). 2 The project was based on the rationale that mine 
safety is a management responsibility and that the adher- 
ence to safety rules and regulations depends in large part 



on the attitude of supervisors and their ability and willing- 
ness enforce safe work practices. 

Although management training absorbs millions of 
dollars each year, few, if any, studies have inquired what 
kind of training has relatively lasting effects. Most train- 
ing evaluations are content with determining whether the 
trainees had found the instruction interesting and had 
learned from it. A followup over a 5-yr period is unique in 
the training literature. This paper briefly describes a 
method of management training, and data on the mine's 
safety and productivity during the subsequent 5-yr period 
after training. 



THE DEMONSTRATION PROJECT 



The Texasgulf trona mine in Granger, WY, was the 
site of the demonstration program. It is one of four trona 
(or soda ash) mines located within a 10-mile radius about 
50 miles from Rock Springs, WY. This area produces 
nearly all the trona ore in the United States. 

The four mines in the Granger area are quite com- 
parable. They operate in the same geological formation, 
and generally use similar technology; their workforce is 
drawn from the same labor pool, and many miners had 
worked in several of these mines over the years. Needless 
to say, all mines routinely conduct the individual safety 
training mandated by the Mine Safety and Health Admin- 
istration (MSHA). 



1 Professor of psychology, University of Washington, Seattle, WA. 
2 Italic numbers in parentheses refer to items in the list of references at 
the end of this paper. 



The evaluation of the training program was based 
primarily on records the mining companies are required to 
furnish MSHA and the Wyoming State Inspector of Mines 
on the mine's ore production and on accidents and injuries. 
Data were originally obtained for the period 1978 to 1981, 
which included the period immediately prior to, as well as 
the 2 yr following the management training intervention. 
The present study reports additional data obtained for 
1982 to 1985. 

At the time the study began, the Texasgulf Mine had 
been in operation for 3 yr and employed about 500 em- 
ployees, with about half of its employees in its under- 
ground mining operation. The others were employed in 
administration and a crushing mill. Although its produc- 
tivity was relatively similar to other mines in the area, the 
mine's safety record was poor and the number of violations 
reported by MSHA inspectors was quite high (2). 



150 



Individual safety training in the proper use of equip- 
ment and procedures is an essential and indispensable 
part of the total safety program. However, it is the respon- 
sibility of management, and especially the first-line super- 
visor, to monitor and enforce compliance with safety proce- 
dures, rules and regulations. The demonstration project 
also recognized, however, that a safety program has little 
chance for success or long-term survival if it interferes 
with mine operations, and that its acceptance will be as- 
sured to the extent to that it contributes to mine productiv- 
ity. 

The training selected consisted of two well- 
established and tested programs that complement each 
other, namely leader match (3-4) and supervisory skills 
training, behavior modeling, adapted from Goldstein and 
Sorcher (5). 

Leader match takes about 8 h to administer (3-4). It 
is based on Fiedler's contingency theory, which states that 
the effectiveness of a leader or a group depends on two 
interacting variables. These are (1) the leader's primary 
motivation either to accomplish the task or to establish 
and maintain close interpersonal relations with members 
of the group (6); and (2) the leader's power, influence, and 
control over group process (situational control). 

The training consists of three parts. The supervisor 
identifies his or her leadership style by means of a short 
scale, and is then taught how to interpret the score. Sec- 
ond, the supervisor learns to diagnose the leadership situ- 



ation by learning to recognize the signs of relatively good 
or poor leader-member relations, high or low task struc- 
ture and strong or weak position power. The third part of 
the training teaches the leader that his or her leadership 
style will be most effective in certain types of leadership 
situations, and how to match the leadership situation to 
the specific type of personality brought to the task. 

In contrast to other leadership training methods that 
attempt to change the leaders personality or behavior, 
leader match shows the manager how to modify situa- 
tional control so that it matches his or her personality and 
style of interacting with subordinates (rather than trying 
to teach the manager how to change behavior or personal- 
ity). This method has been successfully tested in a number 
of field experiments (7-8). 

Supervisory skills training was developed at the Gen- 
eral Electric Co. The version used consisted of eight short 
videotaped vignettes to illustrate how effective mine su- 
pervisors handle such common problems as dealing with 
an irate employee, disciplining a subordinate, or reinforc- 
ing safe behavior. Groups of 8 to 12 supervisors view the 
vignettes, discuss the learning points, and role play the 
situations. The training emphasizes common leadership 
problems faced by the supervisor, and focuses on concrete 
supervisory skills in handling employee problems. The 
training, adapted from Goldstein and Sorcher (5), requires 
about 16 h. Several studies have validated this method 
(8-9). 



TWO-YEAR ASSESSMENT OF THE PROGRAM'S EFFECTIVENESS 



The first evaluation of the training program was con- 
ducted in 1981 (2). It indicated that both productivity and 
safety had improved substantially during the 2 yr after 
training. The productivity of the demonstration mine was 
0.06 pet above the industry average when the study began, 
but 7.0 pet above the industry average in 1982, 2 yr after 
training. Likewise, the number of accidents and injuries 
was 226 pet above the industry average before the training 



but dropped to less than 2 pet above the industry average 
2 yr after the training intervention. In addition, citations 
by MSHA for safety violations had decreased by almost 90 
pet over the level of the years immediately preceding the 
training. At the same time, an employee job survey con- 
ducted by an independent company, showed that satisfac- 
tion with the company's safety efforts had improved by 24 
pet in the underground mining operation. 



THE FIVE-YEAR FOLLOWUP STUDY 



It is important to note that the years 1980 to 1984 
were a very turbulent time for the demonstration mine. 
Among these events were, successively, a proposed expan- 
sion of the mine, a plane accident that caused a major loss 
of senior company officials, and the acquisition of the com- 
pany by a French conglomerate. All of these events caused 
uncertainty and anxiety. In addition, the trona mining 
industry was severely depressed by the strong economic 
downturn that especially affected its major customers, the 
automobile and construction industries. 

Trona cannot be stored for a long period of time, and 
a declining demand for the product necessitated reduc- 
tions in trona mining operations. In order to retain its 
skilled workforce, Texasgulf assigned many of the miners 
to development and maintenance activities. This meant, 
however, that the ratio of tons per employee-hours re- 
portable to MSHA no longer reflected mine productivity; 
an unusually high proportion of miners were now assigned 



to nonproduction tasks. The demonstration mine therefore 
measured its own productivity on the basis of the number 
of miners who were actually assigned to ore extraction. 
Unfortunately, it was not possible to obtain a similar 
measure of productivity from the comparison mines. 

RESULTS BASED ON OBJECTIVE DATA 

The 5-yr followup study was based, insofar as possible, 
on official records using data similar or identical to those 
obtained in the 1981 study. These again included tons of 
ore per employee-hour, and number and severity of acci- 
dents per 200,000 employee-hours (as determined by the 
number of employee days lost). The number of MSHA cita- 
tions for safety violations was also obtained. According to 
comments by mine managers and MSHA safety inspec- 
tors, a low number of citations reflects safe working condi- 
tions and a high level of support for safety regulations by 



151 



management. In addition, data were obtained from the 
demonstration mine which, as already mentioned, calcu- 
lated tonnage per scheduled production hour to reflect the 
reassignment of skilled employees to development and 
maintenance work. 

Figure 1 shows worker productivity in tonnage per 
employee for the Texasgulf Mine and the industry. In 6 of 
the 7 yr, the Texasgulf Mine showed a better production 
record than the average of other trona mines in the indus- 
try. This is especially noteworthy in the years immedi- 
ately after the management training intervention. The 
sole exception was the year 1983, in which the Texasgulf 
Mine production fell substantially below the industry av- 
erage. 

As already mentioned, the Texasgulf Mine diverted 
many of its skilled workers to nonproduction tasks in order 
to retain their services during the severe slump in trona 
demand. For this reason, the mine used tonnage of sched- 
uled production per employee-hour. The data in figure 2 
thus present a more accurate reflection of the mine's ac- 
tual productivity. It can now be seen that productivity at 
the mineface increased throughout 1980, the period for 
which these data are available. The apparent decrease in 
productivity in 1983, therefore, should be seen as an arti- 
fact of measurement. 

The demonstration mine also steadily reduced the 
number of safety violations during the past years. Al- 
though the number of citations issued to all of the mines 
in the study has generally decreased since 1979, the 
demonstration mine further improved its safety record 
over the comparison mines. Since the intervention, the 
demonstration mine reduced the number of citations is- 
sued by MSHA by more than 80 pet of the baseline year 
(fig. 3). 

Furthermore, the reportable rate of accidents and in- 
juries also decreased dramatically at the Texasgulf Mine, 
when compared to the industry average for the available 
years, and beyond that time for the years 1983 and 1984 
(fig. 4). Finally, figure 5 shows the accident severity for the 
1978-84 period. As can be seen, severity of accidents and 
injuries, measured by number of employee days lost be- 
cause of accidents, steadily declined since 1979. 




1980 1981 1982 1983 1984 

Figure 2.— Productivity at the mine face, 1980-84. 




1 984 



Figure 3. — Comparison of Mine Safety and Health Administra- 
tion citation between Texasgulf and trona industry average, 
1979-84. 



2.4 




I979 I980 I98I I982 I983 I984 



Figure 1.— Comparison of worker productivity between Tex- 
asgulf and trona industry average, 1978-84 




KEY 
□ Texasgulf 

■ Industry average 



1 978 1 979 I980 I98I 1 982 1 983 1 984 

Figure 4. — Accident rates for the trona industry as reported 
by the Mine Safety and Health Administration (data on other 
trona mines not available at this time), 1978-84. 



152 




982 1983 1984 



Figure 5.— Relative changes in accident severity at Texasgulf 
trona mine during the 1978-84 period. 



QUALITATIVE EVALUATION 

It would be difficult to interpret the findings without 
knowing about the other major events that might have 
affected productivity and safety in the organization in the 
5-yr period subsequent to training. For this reason six 
mine managers, who could judge the effects of the training 
program in the light of the conditions at the mine since 
1982, were interviewed. These interviews were made on a 
confidential basis by a senior investigator, who had inti- 
mate knowledge of the mine and the original project. 

Those interviewed included 

1. The mine manager, who had joined the management 
team after the end of the training intervention. 

2. The mine production manager. 

3. The surface production (mill) manager. 

4. The director of employee relations, who had been the 
assistant director of employee relations during the origi- 
nal project. 



5. The director of training and safety, who had come on 
site after the end of the training intervention. 

6. One member of the training staff. 

Only the mine production manager had been involved 
in the company's decision to participate in the original 
project. The others did not have a vested interest in the 
project's success or failure, and only one of the managers 
had been directly associated with our program. If any- 
thing, one might expect, therefore, that the interviewees 
would want to play down the effects of the training and to 
emphasize their own role in improving productivity and 
safety. Interviews dealt with three areas 

1. Changes in policy or procedures that might have af- 
fected productivity and safety. 

2. The validity and appropriateness of the various pro- 
ductivity and safety indexes. 

3. Perceptions of the effects of the demonstration project 
training. 

Although they saw the organization from different 
perspectives, all interviewees stated that the mine had 
made very few significant changes in either policy or pro- 
cedures, and that operations in the mine had continued 
relatively unaltered since the time of the training. No 
major changes had taken place in the nonsalaried work- 
force nor had additional training (beyond MSHA require- 
ments) been offered in leadership, supervision, or safety. 

Four of the six managers had remained with the orga- 
nization since the training intervention. They felt that the 
training had brought about significant changes in the way 
managers thought about their jobs, and about productivity 
and safety. They expressed the opinion that the training 
program was responsible in large part for the high level 
of productivity and safety, and they pointed to the current 
quality of supervision as one indication that training had 
beneficial effects. They also mentioned that supervisors 
and executives still occasionally used some of the terms 
they had learned in their training, indicating that they 
had found the concepts relevant to their everyday activi- 
ties. 



SUMMARY AND CONCLUSIONS 



The demonstration program was a case study with 
comparison groups. There is little doubt that both the pro- 
ductivity and safety of the demonstration mine improved 
following the time of the intervention. The average pro- 
ductivity and safety of the other mines in the industry did 
not show similar improvements. There is also little doubt 
that productivity and safety at the Texasgulf Mine have 
remained at this high level or improved still further since 
the intervention. To what extent this improvement is di- 
rectly attributable to the structured management training 
program 5 yr earlier, or is indirectly derived from the 
training is more difficult to say. 

The mine's managers believe that the training im- 
proved both safety and productivity and that the produc- 



tion and safety records support this conclusion. According 
to persons interviewed, management saw the need for 
change; the training program provided the method. Given 
the many other factors that affect the safety and produc- 
tivity of a mining operation, it is truly remarkable that 
these short training procedures seem to have made so 
large a difference in the mine's performance. It is even 
more remarkable that these gains apparently continued 
unabated for at least 5 yr. This study should provide con- 
siderable encouragement to management trainers in 
showing that the effects of short and relatively inexpen- 
sive structured training programs can have substantial 
and long-lasting effects. 



153 



REFERENCES 



1. Fiedler, F. E., C. H. Bell, Jr., M. M. Chemers, and D. Patrick. 
The Effectiveness of Organization and Management Training on 
Safety and Productivity in Metal/Non-Metal Underground Min- 
ing (contract J0287230, Perceptronics, Inc.). BuMines OFR 191- 
84, 1983, 296 pp.; NTIS PB 85-163285. 

2. Fiedler, F. E., C. H. Bell, Jr., M. M. Chemers, and D. Patrick. 
Increasing Mine Productivity and Safety Through Management 
Training and Organization Development: A Comparative Study. 
Basic and Appl. Soc. Psych., v. 5, No. 1, 1984, pp. 1-18. 

3. Fiedler, F. E., M. M. Chemers, and L. Mahar. Improving 
Leadership Effectiveness: The Leader Match Concept. Wiley, 
1976, 28 pp. 

4. Fiedler, F. E., and M. M. Chemers. Leadership and Effective 
Management. Scott-Foresman, 1974, 166 pp. 



5. Goldstein, A. P., and M. Sorcher. Changing Supervisory Be- 
havior. Pergamon, 1974, 133 pp. 

6. Fiedler, F. E. A Theory of Leadership Effectiveness. 
McGraw-Hill, 1967, 299 pp. 

7. Fiedler, F. E., L. Mahar. A Field Experiment Validating 
Contingency Model Leadership Training. J. Appl. Psych., v. 64, 
No. 3, 1979, pp. 247-254. 

8. Burke, M. J., and R. R. Day. A Cumulative Study of the 
Effectiveness of Managerial Training. J. Appl. Psych., v. 71, 1986, 
pp. 232-245. 

9. Wexley, K. N., and G P. Latham. Developing and Training 
Human Resources in Organizations. Scott-Foresman, 1981, 
153 pp. 



154 



MANAGEMENT CONSIDERATIONS IN REDUCING THE ALERTNESS 
PROBLEM AMONG MINE EQUIPMENT OPERATORS 



By Jon A. Wagner 1 



ABSTRACT 



This paper discusses the alertness problems experienced by operators of large mobile 
mine equipment. First, background literature is reviewed, which describes the 
theoretical mechanisms that link various personal and work-related factors to impaired 
alertness and accidents. Second, the results of two mine equipment operator surveys are 
reported, which focus on causes of impaired alertness and possible means of alleviating 
the alertness hazard. Last, recommendations are made, based on the surveys, as to how 
the work-related tasks, environment, and rotation schedules can be modified to improve 
worker maintenance of alertness. It is expected that the improvement of alertness levels 
among mine equipment operators will result in a safer, more productive mining industry. 



INTRODUCTION 



Mine equipment operators - whether they be situated on 
the surface or underground -perform a steady flow of ex- 
cavation or haulage activities that are the lifeblood of the 
mine. These jobs can be exciting and challenging to a new 
worker, but often become repetitious and boring for a more 
experienced worker. However, even the most conscientious 
equipment operator is faced with periods of boring repeti- 
tion. Management thus is faced with a number of potential 
problems, especially when workers report difficulty in re- 
maining awake or staying alert on the job. Consequences of 
such situation may include an increase in accidents, a 
decrease in productivity, and a decline in job satisfaction. It 



■Mining engineer, Twin Cities Research Center, Bureau of Mines, Minne - 
apolis, MN. 



is, therefore, in the interest of both management and 
workers to understand the conditions that lead to impaired 
alertness, and to explore ways in which alertness problems 
can be prevented or alleviated. 

The Bureau of Mines is currently performing research 
towards understanding and improving the most serious 
alertness problems in mining operations. A first step in this 
research is to characterize the mine equipment operators' 
perceptions of their alertness problems. To this end, two 
groups of mine equipment operators (N = 57 and N = 73) 
were surveyed. This paper summarizes the salient results 
from those surveys and discusses management's role in 
maintaining the alertness of mine equipment operators, as 
indicated by these results. 



155 



SCOPE OF THE PROBLEM 



For many years the Bureau has been concerned about 
the number of fatalities and disabling injuries suffered by 
operators of powered haulage equipment used in surface 
mining operations. An analysis (I) 2 of fatalities occurring in 
surface metal and nonmetal mines during the 1972-75 
period showed that 29 pet occurred in the performance of 
haulage operations. Haulage trucks were involved in 75 pet 
of the haulage accidents that resulted in the deaths of 73 
truck drivers. Miller (2) reports that in 1973 alone, accidents 
involving haulage trucks at metal and nonmetal mines 
resulted in 24 fatalities and 643 disabling injuries. Adkins (3) 
studied the haulage truck related fatal and nonfatal injury 
experience during 1978 and 1979. The study shows that 
haulage truck accidents occurring on the haul road and at 
the dump site account for the majority of the fatal and non- 
fatal injuries. These injuries are the result of the operator's 
vehicle colliding with other moving equipment or operating 
haulage trucks that rolled over. 

A review of Mine Safety and Health Administration 
(MSHA) reports of the injury experience for all surface 
metal mining operations in the Nation for the 1978-82 
period indicates that personnel involved in powered haulage 
activities continue to experience one of the highest number 
of fatal and nonfatal injuries of all job classifications 
reported. Table 1 compares the injury and lost workday ex- 
perience of powered haulage with seven other accident 
classifications; powered haulage greatly exceeds the other 
major classifications. Table 2 compares the injury and lost 
workday experience of truck drivers with equipment types 
similar to those included in this study. The data show that 
drivers experience a greater number of fatalities and disabl- 
ing injuries and a greater number of lost workdays. 



Table 1.— Injuries and lost workdays at open pit mines, by ac- 
cident classification, at metallic mineral operations in the United 
States, 1978-82 

Injuries Lost workdays 

Accident classification Fatal NFDL NDL Fatal NFDL 

Powered haulage 18 545 160 108,000 36,672 

Slips or falls of 

persons 2 1,127 363 12,000 32,275 

Handling materials ... . 2 1,344 989 12,000 27,005 

Machinery 5 1,127 363 30,000 16,188 

Hand tool 376 653 6,497 

Electrical 9 43 16 54,000 5,099 

Fall of face or 

highwall 1 9 5 6,000 3,294 

Explosives 1 4 6,000 70 

NDL No days lost. NFDL Nonfatal days lost. 

NOTE.— 1 fatality is charged 6,000 lost workdays, by definition. 



Table 2.— Injuries and lost workdays at open pit mines, by oc- 
cupation at time of injury, at metallic mineral operations in the 
United States, 1978-82 

Injuries Lost workdays 

Occupation Fatal NFDL NDL Fatal NFDL 

Truck driver 7 576 157 42,000 23,967 

Dragline, crane or shovel 

operator 1 117 56 6,000 7,750 

Drill operator 1 179 54 6,000 5,210 

Bulldozer or mobile 

equipment operator . 2 250 105 12,000 5,164 

Front-end loader 

operator 3 87 45 18,000 1,075 

NDL No days lost. NFDL Nonfatal days lost. 

NOTE.— 1 fatality is charged 6,000 lost workdays, by definition. 



ACCIDENT CAUSATION FACTORS 



When one looks for the underlying causes of the ac- 
cidents involving haulage trucks, it is apparent that 
operator error and not defective equipment is the major 
contributing factor. Operator error or human error is often 
caused by lack of alertness, fatigue, drowsiness, preoccupa- 
tion with personal and family problems, and other operator 
concerns. Shiftwork is suspected as a major underlying fac- 
tor contributing directly and indirectly to human error. 

Miller (2) suspects that operator error was the primary 
cause of the accidents he studied. Hulbert (4) reported that 
"... a major cause of haulage truck accidents that resulted 
in fatalities and injuries is driver inattention, or lack of 
alertness." Hulbert grouped the underlying causes of driver 
inattention or lack of alertness as being task and nontask 
related. 

The task-related factors include (a) lack of stimulation of 
the driver because the driving task is highly repetitive and 
(b) rotating shifts at a frequency that does not allow the per- 
son to adjust to the new work schedule or shift. The non- 
task-related factors include loss of sleep; disruption of circa- 
dian cycle; food consumption; use of alcohol, stimulants, or 



2 Italic numbers in parentheses refer to items in the list of references at the 
end of this paper. 



restorative drugs; temporary social and family related 
trauma; and highway hypnosis. Here it is apparent that 
such factors are not easily separated, but are indeed inter- 
related. 

In a paper presented to a group of mine safety and mine 
management personnel, Schuler (5) indicates that rear-end 
collisions involving large haulage trucks are caused by many 
factors, but human factors such as falling asleep while 
operating the truck and lack of alertness because of distrac- 
tion, fatigue, mental strain, and use of medicines, drugs 
and/or alcohol, are of prime importance. Decreased alert- 
ness or unalertness is cited as the prime factor involved in 
rear-end collisions. At the mine cited in the report, the most 
serious accidents occurred during the night shift, because 
the operators had trouble staying awake (one was actually 
napping) while operating the trucks. The study states that 
other mines in the area report similar experiences. No men- 
tion is made of the numerous near accidents, which are 
suspected to occur with greater frequency than an actual ac- 
cident, because of driver unalertness. 

Research into the cause of highway traffic accidents 
estimates that 35 to 45 pet of all single vehicle accidents are 
due to fatigue (6). According to Ferguson (7), fatigue is a 
complex biological phenomenon and is manifested in vary- 
ing degrees in driven aerating over long distances. 



156 



Fatigue reduces the perceptual element and causes an in- 
crease in reaction time. Mental fatigue brought about by ex- 
tended hours of driving is described as a diffuse sensation of 
weariness -a function state between alarm and sleep that 



leads to disordered concentration, reduced alertness, and in- 
creased sleepiness. Of the many causes of medical unfitness 
to drive a motor vehicle over long distances and quick turn- 
arounds, fatigue ranks high. 



OPERATOR ALERTNESS 



A dictionary defines alert as being (a) watchful and 
prompt to meet danger or emergency and (b) quick to 
perceive and act. Unalertness is the antitheses of alertness. 

Surry (9) compares the lack of alertness with the 
phenomenon of the eye looking at an object but not seeing it; 
the information the eye is receiving is blocked or ignored by 
the conscious mind. This phenomenon is the subconscious 
blocking of the information because all information inputs to 
the mind require enormous processing in the brain; in this 
case ". . . the brain seems to be generally less receptive and 
behaves as if in a sleep-like state." 

In a state of alertness, the mind seems to be aware of 
many details in the environment and the person responds 
quickly to given situations. Hulbert (4) indicates that the 
lack of alertness on the part of the haulage truck driver 
"... is a state of mind in which the driver is unable to re- 
spond appropriately to an unexpected situation, or is unable 
to make appropriate steering corrections in time to main- 
tain his truck on the correct pathway." An individual can 
range from being fully aware of environmental activities to 
being completely asleep, from quick response to no response 
to environmental events. 

In the study conducted for the Bureau (4) to evaluate 
monitoring systems to detect the unalertness of drivers, 
eight mines were visited. The researchers interviewed mine 
managers, safety personnel, drivers, and maintenance per- 
sonnel to determine the extent to which lack of alertness 
was involved in haulage truck accidents. The safety person- 
nel and truck drivers admitted that failing to be fully awake 
and being unalert, especially on night shift, contributed to 
the accident potential. 

Hulbert cited a number of task-related factors that were 
felt to be conducive to driver unalertness. The effect of 
these factors are summarized in this way (4): "There is a 
combination of a simple easy-to-drive truck, operating at 
low speeds, in very light traffic, in a high-level noise en- 
vironment, in a sparse, uninteresting terrain, with few, if 
any breaks when the driver leaves the cab, and work shifts 
typically are changed every few weeks; all of which tend to 
result in drivers becoming less alert than they must be in 
order to cope with the driving tasks." 

The report further states that "... anecdotal informa- 
tion given informally in conversations indicates that main- 
taining driver alertness is a matter of concern and that 



unreportable accidents and near accidents are occurring as 
often as once or twice on every shift due to less of alertness 
on the part of the haulage truck operators. In addition to ac- 
tual crashes or near crashes, there are frequent occurrences 
of drivers going to the wrong place, losing their way, "blind- 
ly" following the truck ahead of them to an unwanted loca- 
tion and suddenly "awakening" to realize they had been in a 
semi-alert condition for many minutes while driving." 

McDonald (10) feels that haulage truck drivers are 
unalert because of the routine nature of the haulage job and 
lack of stimulation afforded to the driver. This leads to 
boredom and sleepiness. Boredom (11) is ". . . the feeling ac- 
companying the tendency to revert to restriction of atten- 
tion to inadequately motivated tasks." In other words, a 
bored person restricts his or her attention to the task at 
hand. Boredom is produced by repetition (of monotonous 
tasks), fatigue, depression, and compulsion; daydreaming is 
one of the ways to cope with boredom. 

McDonald (10) also feels that lack of alertness is ag- 
gravated in truck drivers who work on rotating shifts. 
Working on shifts that rotate on a weekly basis does not 
provide the time for the person to physiologically adjust to 
the new rest and sleep schedule. Because of this, drivers are 
out of phase -having trouble staying awake while on duty 
and unable to sleep while off duty. 

The effect of shift work on the human circadian rhythm 
has been studied extensively. This effect is aptly summar- 
ized in the following statement by Ehret (12) ". . . the reason 
shift work, and in particular rotating shift work, leads to 
fatigue, less-than-optimum job performance, worker 
dissatisfaction, accidents and increased health problems is 
because shift work is dyschronogenic. This means that shift- 
work . . . upsets circadian rhythms, the daily, natural body 
rhythms that must be reasonably well maintained in order 
for people to function well on and off the job." 

In sum, human error has been associated with the cause 
of approximately 85 pet of mine accidents (13), and lack of 
alertness has been implicated as the single most important 
factor in human error accidents (2, 14)- In the mining in- 
dustry, the safe behavior of equipment operators is of par- 
ticular concern, because their accidents are often very 
severe and can result in injuries, fatalities, and damage to 
expensive equipment. 



METHOD 



The objective of this study was to gain insight from ex- 
perienced mine equipment operators regarding their 
perceptions of certain factors that may contribute to 
sleepiness and impaired alertness on the job. Specifically, 
the focus of this effort was to further explore the relation- 
ship between alertness and various shift rotation schedules, 



the adjustment to various schedules, the effects of job 
characteristics, and some coping strategies used by these 
workers. Based on the equipment operators' responses to 
survey questions, it is hoped that further insight can be 
gained as to how impaired alertness is caused and how it 
may be treated and prevented. 



157 



Surveys were administered to several independent groups 
of mine equipment operators to obtain data for this study. 
Two mining companies administered questionnaires to their 
employees (total of 40 miners) and a similar questionnaire 
was used by the Bureau to interview seven other miners 
contacted through local labor unions in the Tucson, AZ, 
area. These data were compiled and reported by the Univer- 
sity of Arizona under contract to the Bureau (contract 
H0245001, "Shift Rotation Data on Driver Alertness From 
Large Mobile Mine Equipment Operators"). Through a sec- 
ond Bureau contract (contract S0231056, "Basic Hauling 
Truck Driver Alertness Data," with International Mining 
Consultants), seven groups of surface mine equipment 
operators were surveyed. Each group consisted of nine 
operators of a particular category of equipment (large 
trucks, small trucks, loaders, shovels, etc.) and the surveys 
were specific to equipment type, operating practices, and 
occupation. 



Most of the results presented in this paper are derived 
from data contained in the University of Arizona report. 
The average age of these miners was 40.7 yr. Of the 57 
miners, 50 were male. The average age of the subjects in the 
International Mining Consultants report was 44 yr, with 16 
yr of mining experience. All of these respondents were 
male. 

Although the survey techniques and questions differed 
between groups (no more than nine individuals received 
identical questionnaires from the Bureau), the results are 
compatible and support the same conclusions. Specific ques- 
tions in the surveys were related to the demographics of the 
workers, drug use, work experience, shift rotation, alert- 
ness, naps, sleep length, and sleep quality. In addition, 
survey topics included health habits, work information, 
equipment design, work breaks, beverage consumption, ac- 
cidents, highway hypnosis, and environmental concerns. 



RESULTS 



It should first be noted that both populations surveyed 
had the following pertinent characteristics: (1) the vast ma- 
jority worked on rotating shifts, (2) most respondents drove 
haulage trucks, (3) most respondents worked in large sur- 
face mines, (4) no respondents worked underground, and (5) 
the lunch breaks referred to in these surveys are 20 to 30 
min in duration. 



WORK AND REST SCHEDULING FACTORS 

impaired Alertness and Boredom 

The question, "Do you ever have a problem with alertness 
on the job?", is considered the key question in determining 
whether operators felt they had an alertness problem. Of 55 
respondents, 35 (64 pet) indicated they did have a problem. 
These respondents characterized their lack of alertness as 
being the result of the following factors, in order of 
response frequency: "cannot adjust to shift rotation," 
"boredom," "lack of adequate sleep," "it is difficult to sleep 
during the day," "work is monotonous and repetitious," and 
"cab is too hot." The shift rotation factor was the most com- 
monly perceived problem, and it maybe tied to the problems 
of obtaining adequate sleep. 

This survey also found that 79 pet (45 of 57 respondents) 
became bored while operating their equipment. When asked 
to cite the shifts during which they experienced boredom, 26 
pet cited the day shift, 32 pet the evening shift, and 42 pet 
the night shift. This suggests that boredom is the most 
prevalent during night shift and the least prevalent during 
day shift. 

Time of Day 



3. Table 3 shows the greatest alertness hazard occurring in 
the late night hours, followed by the early night shift and 
day-shift postlunch dip at 1 p.m. 

Another time-of-day element in impaired alertness is 
the fatigue factor. The question and responses in table 4 in- 
dicate that a greater number of persons are aware of the 
drowsiness problem during the night shift, and these per- 
sons become sleepy quite early into the night shift. Although 
it is more pronounced at certain times, drowsiness appears 
to be a problem for a large number of persons on all shifts. 



Table 3.— Response to "what time of day are you most suscep- 
tible to drowsiness, inattention, or impaired alertness," percent 

Day shift: 

8:00 a.m. to 12:00 m 10 

1:00 p.m. to 2:00 p.m 17 

3:00 p.m. to 5:00 p.m 8 

Evening shift: 

6:00 p.m. to 8:00 p.m 1 

9:00 p.m. to 1 1 :00 p.m 5 

Night shift: 

12:00 p.m. to 3:00 a.m 17 

4:00 a.m. to 7:00 a.m 42 

Total 100 



Table 4.— Response to "how soon after starting each shift do 
you start feeling drowsy" 



Shift 

Day 

Evening 

Night 



Av time into 
shift, h 



Respondents 



4.54 
5.18 
3.48 



25 
32 
48 



Rotating Shifts 



Respondents were asked whether they could identify 
particular periods within each shift when they felt prone to 
being less alert. Only 30.5 pet were able to identify such a 
period during day shift, 56.4 pet in the evening shift, and 
88.2 pet during the night shift. This indicates that the 
respondents were more aware of alertness problems during 
night shift than during the other shifts. The time-of-day ef- 
fect is further delineated by the question and replies in table 



One key question asked if working on rotating shifts 
contributed to a lack of alertness on the job. Sixty-nine per- 
cent (35 of 51 respondents) answered yes and 31 pet 
answered no. A possible connection between alertness and 
sleep quantity during work on rotating shifts is addressed 
by three questions. First, when asked if they felt they got 
adequate rest at home while working on rotating shifts, 50 
pet answered no. Next, the miners were asked how much 



158 



sleep they got (see table 5). The responses in table 5 suggest 
that persons working on the night shift experience the 
greatest variability in hours slept, and that they got less 
sleep on the average. This represents a sleep deficit of 14 
pet, when compared to persons working on either day or 
evening shifts. 



Table 5.— Response to "how many hours of sleep do you 
normally get at home while working on rotating shifts" 

Time slept, h 



Shift Range 

Day 5.5- 9.5 

Evening 5.0- 9.0 

Night 3.0-11.5 



Average Respondents 



7.25 
7.29 
6.23 



55 
50 
48 



The third question of this series inquired about the 
number of hours of sleep the respondents felt they normally 
needed. The number of hours ranged from 4 to 10, but the 
average hours of sleep needed was 6.97. This is 11 pet more 
sleep time than the average hours slept by the worker on 
night shift. 

Shift Changes 

The respondents were asked to identify the shift rota- 
tion schedules that were hardest and easiest, respectively, 
on their ability to maintain their alertness on the job. Their 
responses are tabulated in table 6. From table 6, one can 
calculate that 83 pet of the respondents to the question 
found that shifting to night shift from either day or evening 
shifts was hardest on their alertness. Another calculation 
shows that 68 pet found shifting from day to evening and 
from evening to day was easiest for them. It should be noted 
that most people find shifting from day shift to night shift is 
the hardest change, and that no one finds this same rotation 
to be the easiest. 



Table 6.— Response to "which shift changes are hardest and 
easiest on your ability to stay alert" 

Shift change Hardest Easiest 

Day to evening 1 19 

Day to night 23 

Evening to night 16 6 

Evening to day 3 13 

Night to day 3 1 

Night to evening 1 8 

Total 47 47 



Table 7 is somewhat similar but it focuses on sleep 
habits rather than alertness. Responses to the questions cor- 
relate well with the responses to questions about shift 
change and alertness. Seventy percent of the respondents 
found that rotating to night shift from day or evening shifts 
was hardest on their sleeping habits, and 67 pet found that 
rotating from day to evening or from evening to day posed 
the least hardship on their sleeping habits. 

Table 7.— Response to "which shift changes are hardest and 
easiest on your sleeping habits" 

Shift change Hardest Easiest 

Day to evening 3 17 

Day to night 20 1 

Evening to night 12 4 

Evening to day 5 14 

Night to day 5 2 

Night to evening 1 8 

Total 46 46 



An important question is can workers adapt to a new 
shift over time, or do they instead build up a fatiguing sleep 
deficit that tends to nullify any adaptation of their biological 
rhythms. Table 8 offers some information on this subject. 
The responses indicate that an adaptation occurs for the ma- 
jority of workers on a new shift, with only about one-quarter 
of the workers becoming maladaptive. It seems apparent 
that this general population may be best suited to shift 
schedules that allow relatively long periods of time between 
shift changes. 



Table 8.— Response to "do you have more trouble with alert- 
ness on the first days or the last days of a shift cycle," percent 

Response 

First few days 73 

Last few days 27 

Total 100 



Asleep on the Job 

Of 57 respondents, 32 (56 pet) admitted to taking cat- 
naps during work. Further information is provided in table 
9. Of those who catnap while at work, most do not do so dur- 
ing the day or evening shifts. However, of the workers who 
catnap, 97 pet take one or more catnaps during the night 
shift. Of the 32 respondents who indicated they catnap in 
the night shift, 4 admitted to catnapping 9 to 18 times per 
shift. When asked how rested they felt after taking catnaps, 
79 pet of the respondents indicated that they felt rested, 12 
pet did not feel different, and 9 pet felt less rested or more 
sleepy. 



Table 9.— Response to "if you take catnaps, how many do you 
usually take on a shift" 





Shift 


None 


1 or more 


Day 




20 


10 


Evening . . . . 




16 


15 


Night 




1 


32 



Asleep During Breaks 

When asked if they usually slept during their lunch 
periods, 35 of 55 respondents (64 pet) replied in the affirm- 
ative. Of the 44 lunchtime sleepers, 34 (77) pet indicated 
they slept during the night shift lunch break; 14 pet and 9 
pet slept during their lunch periods on day and evening 
shifts, respectively. The relatively high number of night 
shift lunch-break sleepers shows the unusually high value 
placed on rest, especially when considering the attractive 
alternatives of eating a meal or conversing with coworkers. 



Asleep at the Wheel 

A most serious question concerns the occurrence of 
asleep at the wheel episodes (see table 10). Table 10 shows 
that nearly 80 pet of the heavy equipment operators admit- 
ted to falling asleep at the job at least once during each 
night shift. The survey also reported that five respondents 
admitted to falling asleep as many as 9 to 18 times per night 
shift. 



159 



Table 10.— Response to "while operating your equipment, how 
many times per shift do you catch yourself falling asleep" 





Shift 


Never 


1 or 


more 




No. 


pet 


No. 


pet 


Day 


32 
27 
10 


62 
55 

21 


22 
22 

38 


38 


Evening . 
Night . . . 




45 




79 



PERCEPTION PROBLEMS AND ACCIDENT 
CAUSATION 

Highway Hypnosis 

Highway hypnosis is a form of trance induced by exter- 
nal conditions such as monotonous road scenery, constant 
noise of the engine, repetitious vibration patterns, and ex- 
tended driving periods at constant speeds where physical 
action is minimal. To assess the recognition of this 
phenomenon by the operators, a number of questions were 
posed. 

Fifty-three percent of the drivers indicated they had ex- 
perienced hypnosis while operating their equipment. Most 
of them experienced highway hypnosis on night shift while 
driving over long distances (more than 10 min on one leg of 
a haul). Hypnosis most commonly occurred during the mid- 
dle or toward the end of the night shift. When asked about 
hypnotic conditions drivers who had experienced hypnosis 
responded as shown in table 11. 



Table II.— Response to "what condition leads to hypnosis" 

Condition 

Constant noise 29 

High temperature in cab 25 

Constant driving 22 

Same scenery 20 

Constantly looking at road 19 

Long drive uphill 18 

Prolonged driving 17 

Vibration 13 

Eating 3 



The next question asked (table 12) attempted to cor- 
relate the number of hypnotic episodes with the shift in 
which the events occurred. The data suggest that not as 



many people experience highway hypnosis during the day 
shift as in the night shift, and operators experience increas- 
ing episodes of hypnosis in a progressive manner while 
working day, evening, and night shifts, respectively. 



Table 12.— Response to "how often do you realize that you have 

been driving your equipment but you don't remember the events 

of the past few minutes" 

Shift Respondents^ 

Day 15 

Evening 22 

Night 36 

'Answering more than once per shift. 



Accidents 

Of 56 respondents, 37 (66 pet) indicated they had been 
involved in one or more accidents. Where specific accidents 
and shifts in which they occurred are mentioned, the ac- 
cidents occurred as follows: 20 on day shift, 13 on evening 
shift, and 17 on night shift. 

When asked if any of the accidents were caused by the 
equipment operators' lack of alertness, 13 of 36 respondents 
(36 pet) answered in the affirmative. In addition, 47 of 52 
respondents (90 pet) thought that working rotating shifts in- 
creased a person's chances of having an accident. The ques- 
tion in table 13 addresses the reasons why an alert driver 
may avoid accidents. 



Table 13.— Response to "would an emergency situation, such 

as a front tire blowout, be handled better by a driver who was 

more alert," percent 

Response: 

Yes 96 

No 2 

No effect 2 

Total 100 

Explanation: 

Better reflexes 66 

Anticipation 20 

Other _J4 

Total 100 



CONCLUSIONS FROM SURVEYS 



Two-thirds of the respondents indicated that lack of 
alertness is a problem. Over half of the respondents admit- 
ted to taking catnaps during work. It is, therefore, clearly 
reported that impaired alertness and sleepiness is prevalent 
during work. Of those workers who do catnap, most usually 
did it on the night shift, although it does occur to a lesser ex- 
tent on the day and evening shifts. The percentage of 
workers who stated that they have regularly fallen asleep 
while operating equipment at least once during each 
workshift is highest during night shift duty (79 pet) and 
lowest during the day shift (38 pet). 

As it has been shown, shift work, night work, and shift 
changes all have a discernible impact upon the alertness pro- 
blem. Some effects of shift rotation include reduced alert- 
ness, chronic fatigue, sleep deficit, disruption of sleep and 



eating patterns, and disruption of social life. Also, it appears 
that (1) weekly rotation does not allow most operators 
enough time to adjust and feel normal, (2) shifting from day 
shift to night shift is hardest on alertness and sleep, (3) all 
adverse effects of shiftwork are greatest on the night shift, 
(4) the first few days of a new shift are the most difficult in 
which to maintain alertness, and (5) the period from 4 a.m. 
to 7 a.m. is the time in which equipment operators are most 
susceptible to impaired alertness. 

Finally, it is also apparent that alertness can be main- 
tained, or at least restored, by incorporating certain 
changes in the way tasks are performed and by modifying 
shift rotation schedules. Other survey data not discussed in 
this paper reinforce these ideas. In general, the respondents 
felt that the following changes would reduce the lack of 



160 



alertness problem: (1) allow operators to select the shift 
they prefer and remain on that shift continuously, (2) rotate 
shifts less frequently than once a week, (3) provide air condi- 
tioning, (4) allow operators to swap equipment to alleviate 
boredom, and (5) do not keep the haulage truck driver on the 



same haul route throughout the entire shift. In addition, 
operators rated getting out of the equipment, conversing 
with coworkers, and performing a variety of job 
assignments as being the most important activities in main- 
taining alertness. 



MANAGEMENT CONSIDERATIONS 



After reviewing this survey information, mine 
managers and safety directors may wish to consider 
whether their operators work under any of the same condi- 
tions as the operators surveyed. If so, managers should 
become more aware of the specific alertness problems their 
operators face. This can be accomplished through informal 
interviews or formal company or union surveys. If there are 
indeed reports of falling asleep at the wheel, difficulty in 
maintaining alertness, or even just excessive boredom, 
managers may wish to consider various changes that may 
prevent unalertness and accidents. 

CHANGING THE NATURE OF THE JOB 

According to the surveys, boredom, monotony, and 
repetition were named as important causes of impaired 
alertness. Also, constant driving, prolonged driving, and 
driving past the same scenery were often cited as conditions 
leading to hypnosis. To combat these problems, the survey 
respondents made a number of reasonable suggestions that 
may be implemented under the right circumstances. Follow- 
ing is a list of possible changes that may be made to job 
tasks, plus some apparent drawbacks to these changes. 

1. Allow operators to swap equipment during a 
shift. - This action will undoubtedly result in at least a tem- 
porary increase in alertness, especially if a miner swaps 
equipment types, as well. For instance, a haulage truck 
driver would probably become highly alert after swapping 
his or her vehicle for a front-end loader. However, some 
potential drawbacks include the necessity of cross-training 
and the problem of seniority rights in union environments. 
Also, the equipment swaps should not require extra time or 
travel, but would likely do so unless the workers normally 
meet at a central point for lunch, maintenance, or produc- 
tion activities near midshift. Another potential problem is 
that certain jobs may require substantial practice on each 
shift before the operator can become optimally productive 
and operate in a safe manner; equipment swaps may not 
allow this. Last, supervisors may need to deliver instruc- 
tions at least twice if equipment swaps occur. All in all, 
equipment swapping may be a reasonable means of main- 
taining alertness (and morale) as long as the operators are 
sufficiently versatile and productivity is not adversely af- 
fected. 

2. Vary the haulage routes of truck drivers throughout 
the shift. -This action will ensure changing scenery, which 
will alleviate visual boredom. Also, route changes to and 
from high-traffic and low-traffic areas should provide some 
necessary mental stimulation. Drawbacks to this approach 
are that multiple haulage routes are not always available, 
especially in smaller mines with only one excavator work- 
ing, and that supervisory control of haul route assignment 
changes may be difficult to maintain without two-way radio 
contact. An ideal situation is a minewide truck dispatching 
system, where haulage is monitored and controlled by a 



computer-sensor network, facilitating instantaneous route 
changes for purposes of efficiency. A system such as this is 
not only extremely productive, but operators now become 
"part of the game" and are able to view changes in scenery 
(15). 

3. Encourage brief exercise breaks whenever there are 
work delays or when workers become excessively 
sleepy. - Often, a quick 5-min break whereby the operator 
disembarks from his or her equipment and takes a walk, 
runs in place, or does jumping jacks, may be enough to 
restore lost alertness. Relatively intense physical activity in 
fresh air, free from equipment vibration, will result in im- 
mediate increases in heart rate, metabolism, blood pressure, 
circulation, respiration rate, and alertness. Also, the energy 
surge brought about by exercise may last for a period of 
hours beyond the time of exercise. Such exercise may be 
particularly important for older operators whose general 
health problems include poor circulation and heart function. 
Of course, drawbacks to exercise breaks include operational 
problems (how can the operator be contacted if he or she is 
away from the radio?), disciplinary problems (how can abuse 
of breaks or excessive break time be avoided?), and logistical 
problems (where can an operator safely exercise in uneven, 
rocky, or muddy terrain?). In addition, some workers may 
be used to dozing off during work delays and may not be 
readily motivated to exercise. However, if exercise can be 
achieved without the aforementioned problems, increased 
alertness should result. 



CHANGING THE JOB ENVIRONMENT 

Many equipment operators are subjected to high 
temperature, constant noise, and detrimental vibrations 
during the full term of the work shift. Each of these en- 
vironmental stressors can affect alertness, and workers 
themselves have reported difficulties related to them. 
Following are three ways in which the work environment 
can be changed to promote improved alertness maintenance 
and overall performance. 

1. Where needed, install adequate air conditioning and 
ventilation systems in the cabs of mobile mining 
equipment. -Even though a slightly warm cabin 
temperature of 80° F may result in optimal performance for 
many operators, temperatures above this usually bring 
about tiredness and drowsiness. Conversely, cabin 
temperatures below 60° F can hinder concentration, coor- 
dination, and circulation. Therefore, the cabin environmen- 
tal control system should allow a temperature range be- 
tween 60° and 80° F, not only for operator comfort but for 
occasional blasts of "cold" or "hot" air to stimulate operators 
during times of drowsiness. Highway drivers often benefit 
from simply rolling down a window for a change in 
temperature; unfortunately, mine equipment operators do 
not always have this option, because of dust and/or other 



161 



contaminants or fumes in the mine air. The only real 
drawback to air conditioning is the initial cost. However, the 
potential benefits include improvements in alertness, safety, 
performance, comfort, and employee morale, especially in 
mines located in hot regions of the country. 

2. Break up the monotony of constant equipment noise by 
allowing the use of both one-way and two-way radios. -One- 
way radios (receivers) and cassette players allow each 
worker to play the kind of music that stimulates him or her. 
Two-way radios give the operator the opportunity to know 
what is going on in the mine, as well as allow stimulating 
conversation in time of need. Both radio types provide im- 
portant cues (music, voices) that can arouse and stimulate a 
drowsy mind. A logical concern is that such devices may 
draw attention away from the job at hand, or may lead to a 
situation where the operator is bombarded with too many 
sources of stimuli and becomes overstressed. However, 
given the nature of the job tasks revealed in the surveys, 
this stimulation is badly needed. Possible abuses of radio use 
include playing music too loud to hear warning signals, and 
the tieup of two-way radios, effectively preventing receipt 
of emergency radio calls. 

3. Decrease the levels of vibration and noise transferred 
to the worker. -Excessive noise and vibration can bring 
about physical as well as alertness decrements. Constant 
loud engine rumble and cabin sway, especially during uphill 
climbs of trucks and locomotives, seem to present a definite 
alertness problem for drivers. To combat noise, the installa- 
tion of acoustic insulation to engine and/or cabin compart- 
ments can reduce engine noise to more tolerable levels. Pro- 
tective ear wear may also be encouraged. For vibration 
reduction, state-of-the-art adjustable seats utilizing 
hydraulic or pneumatic damping systems can eliminate 
most of the high-frequency vibrations before they reach the 
operator. (Unfortunately, low-frequency vibrations that 
sway the operator have not yet been eliminated by either 
state-of-the-art seating or equipment suspension systems.) 
Other than the cost of providing noise and vibration reduc- 
tion in the operator cab, a realistic concern is whether such 
measures will provide the operator with too comfortable a 
station, thereby leading to decreased alertness. The 
operators themselves, of course, do not share this concern; 
however, more research is needed to determine if there are 
negative performance effects resulting from an extremely 
high degree of operator comfort. 



CHANGING LIFESTYLES TO IMPROVE 
ALERTNESS 

Though it is not deduced explicitly from the operator 
surveys, other research suggests that workers' lifestyles 
contribute heavily to their on-the-job state of alertness. 
Managers can promote healthier lifestyles through educa- 
tion and training, wellness promotion programs, and 
employee assistance programs. The following points il- 
lustrate the major components of a lifestyle that will allow 
an operator to function at his or her best on the job: (1) 
weight control and adequate nutrition, (2) cardiovascular 
fitness through aerobic exercise, (3) abstinence from drug 
and alcohol abuse, (4) abstinence from tobacco products, and 
(5) adequate quantity and quality of sleep. Of these five 
points, the importance of getting adequate sleep was most 
strongly supported by the operator surveys. 



CHANGING THE WORK SCHEDULE 

Many of the survey's questions and answers focused on 
the effect of the work schedule on operator alertness. As 
mentioned earlier, both shift rotation and night work in 
general were perceived to cause problems with alertness 
and sleep habits. To alleviate these problems, the 
respondents reported a desire to either lengthen the period 
of time between shift rotations or to allow the workers to 
select a shift and remain on that shift permanently. In each 
case, the respondents showed their belief that 5 to 7 days on 
a shift was inadequate for their adaptation, affecting both 
life on the job and life and rest at home. 

The question facing managers today is, "what is the 
optimum work schedule?" In mining and other heavy 
industries, a myriad of schedules exist, each with its advan- 
tages and shortcomings. Unfortunately, few valid com- 
parisons or carefully constructed research efforts have been 
made regarding the safety of work schedules in the mining 
environment. There are, however, laboratory data available 
that can supply theoretical guidelines for the design of work 
schedules. Some of the options to be considered are as 
follows. 

1. Lengthen the period of rotation to allow further adap- 
tation to the new shift. -For instance, rotate every 3 or 4 
weeks instead of every week. One mining operation 
reported a high degree of success in terms of health, produc- 
tivity, and satisfaction after switching from weekly to 
triweekly rotations (16). Shift rotation, by its nature, is fair 
in that it makes sure everyone works each shift the same 
amount of time. However, a longer period of time on each 
shift may give workers a more adequate opportunity to 
make plans and establish routines. 

2. Change the direction of rotation from backward to for- 
ward. -Most shift rotation schedules now rotate 
backwards, meaning that the next new shift begins 8 h 
earlier, rather than 8 h later than the old shift. This 
backward rotation works against the human body's natural 
circadian (daily) rhythms, which tend to prepare a body for a 
forward rotation. Previous studies have shown that it takes 
twice as long for a body to adjust to a backward rotation 
versus a forward rotation (17). 

3. Allow qualified workers to work permanently on night 
shifts. - Though most workers will probably not want to do 
this, the few who do will greatly decrease the number of 
workers who must otherwise rotate through night shift. It is 
important to remember, however, that permanent night 
shifters may feel isolated from the mainstream of activity, 
and such isolation can result in lowered morale. Also, the 
availability of moonlighting jobs is great for permanent 
night workers. For these reasons, management should be 
careful to choose competent, dedicated, and motivated 
workers for permanent night shift, and should pay extra at- 
tention to the managerial needs of such workers. 

4. Where safety is not a major concern, shorten the 
period of rotation to prevent any partial adaptation to non- 
day shifts. -For instance, rotate every 1 or 2 days instead of 
every week. This system, called rapid rotation, is currently 
used in various forms in many European countries and is 
popular among the workers. Workers maintain their basic 
diurnal (day-active) rhythms while fighting through brief 
periods of night work. Fortunately, this makes a high quan- 
tity of prime social time available each week, without the 
constant feelings of fatigue that often characterize weekly 



162 



rotations. However, night work is subject to increased er- 
rors, as workers work through the alertness trough (1 to 5 
a.m.) without the benefit of any partial adaptation. Thus, 
such a schedule should be practiced only among those oc- 
cupations where safety is not an issue and increased night 
time error rates can be well tolerated. This may well be the 
case with certain office and clerical workers within the min- 
ing industry. 

Of course, many other scheduling options exist, in- 
cluding the use of extended workdays (10 and 12 h), com- 
pressed workweeks (3 or 4 days), noncontinuous schedules 
(e.g., two 10-h shifts per day), part-time fill-in crews, non- 
crew schedules, the use of overtime, and five-crew 
schedules. However, the major parameters determining 
safety are the four previously listed. 

Possibly more important than choosing the optimum 
work schedules for a mine is the manner in which this 
schedule is chosen and implemented. The process of 
schedule modification should educate and harmonize all in- 
terested parties. It might even be true that the so-called op- 
timum schedule turns out to be the current one; but if the 
managerial interactions leading to the final decisions are 
constructive, rational, open, and informed, then employee 
relations will be enhanced as an important side effect. Such 
a schedule modification process should have a win-win-win 
scenario, whereby management, safety, and labor personnel 
all reap benefits from both the process and the improved 
schedule itself. 

Anecdotal information derived from stories of both suc- 
cesses and failures in changing shift schedules provides 
some important points to remember when considering a 
schedule change. First, there is no universally optimal 
schedule. What works at one mine may not work in another 
because of different operational and human requirements. 
Second, once a schedule change is made, it is extremely dif- 
ficult to make another change within a short period of time. 
Thus, the process of selecting a new schedule ought to be 
conducted with very careful considerations. Third, im- 
proved schedules may be met by worker resistance unless 
worker suspicions and fears are alleviated. In sum, the 
schedule selection process requires a methodology that is 
both systematic and likely to be accepted by the workers. 
Following are recommended guidelines for choosing and im- 
plementing the optimum work schedule for a mining opera- 
tion. Note that the actual procedure will probably vary 
depending on size, needs, and problems of the particular 
company. 

1. Construct a committee made up of representatives 
from top-to-bottom management, safety, and labor. -This 
committee should work openly, encourage participation 
from all potentially interested parties, and be semiperma- 
nent in nature. The remainder of the steps in the following 
procedure will be conducted via this committee. It is 
especially important that no particular group of workers or 
job classification be excluded from committee activities, 
because the excluded group will then resist any schedule 
changes that are recommended. 

2. Evaluate the specific on-the-job problems and needs of 
the mine's particular worker population. - The optimum 
work schedule can only be designed when the 
characteristics of the specific population are known. To per- 
form this evaluation, the shiftwork committee should ex- 
amine accident records, health records, and productivity 



levels to see if any shift-related trends appear. Of special in- 
terest are accidents occurring on the first few night shifts, 
on the last few night shifts, and during the alertness trough 
from 1 to 5 a.m. Also, incidences of naptaking, sleeping on 
the job, and dozing off should noted. Health records, if 
available, may reveal excessive incidences of gastritis, diar- 
rhea, or other digestive disorders, and depression, which 
are also clues of schedule-related problems. Productivity 
fluctuations during and between shirts should also be noted. 
Next, informal interviews should be conducted with a 
sampling of workers to ascertain what general schedule- 
related problems are noted by the workers. From these in- 
terviews, a list of major concerns should become apparent 
to the committee members. At this point a survey can be 
given to the entire population that elaborates on the con- 
cerns of the workforce. For instance, if interviewed workers 
report various sleeping problems, a survey can specifically 
ask when these problems occur, how much sleep is actually 
attained, and what could be done to alleviate these prob- 
lems. Later, after a new schedule has taken effect, the 
workers can be surveyed again to see how comparatively 
beneficial the scheduling change has been. A final step in 
problem evaluation may be to have willing employees keep 
diaries noting sleep times, meal content and timing, and 
mood variations through a full shift cycle. A health-care pro- 
fessional should then examine the diaries, note schedule- 
related problems, and possibly recommend immediate 
courses of action such as special diets or sleep strategies. 

3. Determine the social and operational requirements of 
the work schedule. - It is necessary to determine, through 
the committee, the social and operational constraints to be 
considered when designing the new schedule. For instance, 
married workers may highly value having free time in the 
afternoons for family life; single parents may instead prefer 
to have day hours free to avoid child-care costs. Hunters and 
fishermen may be able to pursue their sport on short notice 
during any daylight hours; high school sports fans may in- 
stead strongly prefer to have afternoons free. Also, the in- 
crease in two-earner households makes the work schedule of 
the spouse an important consideration. 

Operational requirements include number and timing of 
shifts required to produce a product and the limits on hours 
workers may work to fulfill legal or cost requirements. 
Because of high overhead costs, continuous furnace opera- 
tion, low-stockpile capacity, or high production re- 
quirements, some mines must operate on a continuous, 
24-h/d, 7-d/week basis. However, other mines or mine crews 
may need to produce less than continuously. These produc- 
tion requirements should be ascertained and made known to 
the shiftwork committee. 

4. Design alternative work schedules. - Utilizing infor- 
mation about the human body, the needs of the workers, 
and the requirements of the operation, a number of alter- 
native work schedules should be designed. No design should 
be thrown out as yet; each design may have a valid 
characteristic that can be eventually utilized. Schedules can 
be drawn companywide or departmentwide. During this 
stage, other mines and industrial companies should be con- 
tacted for ideas of how different schedules can be con- 
structed. It is estimated that over 4,000 schedules are cur- 
rently in existence, yet the best schedules are probably 
designed from scratch for the particular needs of a specific 
company. 



163 



5. Evaluate the alternative work schedules. -Each alter- 
native should be rated according to the following criteria: 

a. How compatible is it with human circadian 
rhythms? 

b. How easily will it be accepted? 

c. How well does it meet operational requirements? 

d. How well does it generate social time, in terms of 
quality and quantity? 

e. What are the labor costs associated with it? 

f. Does it meet legal requirements for wages, hours, 
and salaries? 

g. How simple is this schedule to remember? 

h. How many weekends off per month are included? 

i. How acceptable is it to the line supervisor? 

j. How well does it blend with current seniority prac- 
tices? 

k. How much time does it allow for training? 

1. How amendable is it for workero wishing to trade 
shifts? 

m. How difficult will it be to cover absentees? 

Each of the above questions can become quite complex, 
especially question a. Biological compatibility relates to the 
worker's ability to adapt to a new shift, maintain a high 
degree of alertness on the job, and get adequate rest be- 
tween workshifts. Again, specific population characteristics 
are important to consider. For instance, younger workers 
(18 to 30 yr) may be able to function quite well with a 
relatively biologically incompatible schedule. However, 
older workers (45 + yr) may experience severe sleep, diges- 
tion, and alertness problems with the same schedule, 
because of common physiological changes (18). 

6. Choose the three best alternatives for further discus- 
sion and a committee vote. - Once the committee has voted 
and chosen the most promising new schedule, the workers 
should be informed about the choice and polled to determine 
their willingness to try the new schedule for a trial period of 
between 6 months and 1 yr. A clear majority should show 
such a willingness. If some sections or departments of the 
mine are very willing to try the new schedule compared to 
others, it is better to implement the new schedule only 
among the most willing sections. If the new schedule is in- 



deed better, word of mouth will sell it to the less willing sec- 
tions at a later date. 

7. Once the new schedule is implemented, the effects of the 
schedule change should be evaluated 
comprehensively. -Evaluations should take place after 
about 3 months (when the workers begin to get used to it) 
and again after about 9 months (after the "honeymoon" is 
over). Sources of data for this evaluation include accidents 
records, productivity measures, health reports, 
absenteeism-tardiness records, worker interviews, reissued 
surveys, and diary information. The shiftwork survey 
should elicit specific information about the new schedule's 
effect on sleep habits, alertness, job satisfaction, and social 
life. 

8. Inform the workers about the results of the evalua- 
tions. - Workers need to know how the new schedule affects 
the overall cooperation, in both positive and negative man- 
ners. Only after such education occurs, can workers then 
make an informed decision about adopting or rejecting the 
new schedule. Without the big picture, workers may tend to 
overvalue their personal opinions at the expense of the rest 
of the workforce. Of special emphasis are overall workforce 
changes in sleep, diet, and alertness. 

9. After 1 yr on the new schedule, either the committee or 
the total mine population may vote to keep or reject the new 
schedule. - In either event, the process of choosing and im- 
plementing an experimental schedule is not yet complete. 
First, after understanding the problems the workers have 
with the chosen work schedule, a training session should be 
offered by the committee on how they can best cope with the 
stresses of shiftwork. Such a training session may contain 
advice on how to obtain adequate sleep during the day, how 
to plan meals to prevent digestion problems and provide 
adequate energy, and how to incorporate social and family 
activities into a shiftworking lifestyle. Family attendance at 
this training session is strongly encouraged. Second, the 
committee should meet at least yearly to discuss complaints 
about the current schedule, discuss new developments 
affecting shift scheduling, and briefly assess the scheduling 
needs of the current mine population. As the worker pool 
experiences turnover, aging, and lifestyle change, the needs 
of the workers can indeed change quite drastically in a 
relatively short amount of time. 



CONCLUSIONS 



Though powered haulage-type accidents are prevalent 
in the mining industry, especially among haulage truck 
drivers, management has a number of options available to 
reduce this safety problem. One such approach is the reduc- 
tion of human error, to which impaired alertness is a 
primary contributor. Mine equipment operators themselves 
report that job tasks, environments, and work schedules all 



impact operator alertness. Therefore, based on worker 
surveys and other scientific research, recommendations are 
made to alleviate the alertness hazards. By making certain 
job modifications via a rationale process, operator alertness 
can be enhanced and employee relations can be improved as 
an important side benefit. 



164 



REFERENCES 



1. Kendall, J. M. Analysis of Surface Fatalities at Metal and 
Nonmetal Mines, 1972-75. MSHA Health and Safety Analysis 
Center (Denver, CO), 1976, 19 pp. 

2. Miller, W. K. Analysis of Truck Related Fatalities and Disabl- 
ing Injuries at Metal and Non-Metal Mines. MSHA IR 1022, 1975, 
8 pp. 

3. Adkins, G. E., J. L. Dahle, and L. Owens. Novel Cab Design 
Concepts To Improve Large Haulage Vehicle Safety (contract 
J0295013), Woodward Associates, Inc.). BuMines OFR 122-83, 
Nov. 1982, 152 pp.; NTIS PB 83-221085. 

4. Hulbert, S. F., R. J. Dompe, and J. L. Eirls. Driver Alertness 
Monitoring System for Large Haulage Vehicles (contract 
H0282006) Tracor MBA). BuMines OFR 119-83, 1982, 120 pp.; 
NTIS PB 83-220640. 

5. Schuler, G. Haulage Truck Rear-End Collisions. Pres. at 
Southwest Safety Congr. Univ. Arizona, Tucson, AZ, Mar. 9, 1976; 
available from M. M. Garcia, Univ. AZ, Tucson, AZ. 

6. Egelund, N. Spectral Analysis of Heart Rate Variability as an 
Indicator of Driver Fatigue. Ergonomics, v. 25, 1982, pp. 663-672. 

7. Ferguson, A. L. Drivers Fatigue. South Afr. Med. J., v. 64, 
Sept. 24, 1983, pp. 489-490. 

9. Surry, J. Industrial Accident Research: A Human Engineering 
Appraisal. Occupational Health and Safety Div., Ontario Ministry 
of Labor, Toronto, Ontario, Mar. 1979, 203 pp. 

10. McDonald, L. B. The Sleepy Mine Driver. Paper in Pro- 
ceedings of 1977 National Safety Congress, Mining Session, Na- 
tional Safety Council and Exposition, Chicago, IL, Oct. 1977, 
pp. 37-44. 



11. Smith, R. R. Boredom: A Review. Human Factors, v. 23, 
No. 3, 1981, pp. 329-340. 

12. Ehret, C. F. Applied Chronobiology: Helping Shift Workers 
Beat Circadian Vertigo. Argonne Natl. Lab., v. a, No. 2, 1983, 
pp. 3-8. 

13. Consolidation Coal Co. (Pittsburgh, PA). Cost/Benefit 
Analysis of Deep Mine Federal Safety Legislation and Enforce- 
ment. Dec. 1980, 165 pp. 

14. Treat, J. R., N. S. Tumbas, S. T. McDonald, D. Shinar, R. D. 
Hume, R. E. Mayer, R. L. Stansifer, and N. J. Castellan. Tri-Level 
Study of the Causes of Traffic Accidents: Final Report-Executive 
Summary (U.S. DOT NGTSH contract DOT-HS-034-3-535, Inst, 
for Res. in Public Safety, Indiana Univ.). Rep. DOT-HS-805-099, 
May 1979, 78 pp. 

15. Eggert, K. Update of Mine Truck Dispatch. Proceedings of 
60th Annual Meeting of the Minnesota Section AIME, Jan. 14-15, 
1987. Univ. MN, 1987, pp. 4-1-4-5. 

16. Czeisler, C. A., M. C. Moore-Ede, and R. M. Coleman. 
Rotating Shift Work Schedules That Disrupt Sleep Are Improved 
by Applying Circadian Principles. Sci., v. 217, July 30, 1982, p. 460. 

17. Czeisler, C. A., G. S. Richardson, R. M. Coleman, J. C. Zim- 
merman. M. C. Moore-Ede, W. C. Dement, E. D. Weitzman. 
Chronotherapy: Resetting the Circadian Clocks of Patients With 
Delayed Phase Insomnia. Sleep, v. 4, No. 1, 1981, pp. 1-21. 

18. Akerstedt, T. Interindividual Differences in Adjustment to 
Shift Work. Studies of Shiftwork, ed. by W. P. Colquhoun and 
J. Rutenfranz. Taylor & Francis (London), 1980, pp. 121-130. 



165 



SIMPLE COMPUTERIZED DECISION-SUPPORT SYSTEM 
FOR MANAGING COAL MINE PRODUCTIVITY 



By Robert F. Randolph 1 



ABSTRACT 



This paper presents a simplified decision support system for improving coal mine 
productivity. The Department of Energy funded a study in which a production-function 
approach was used to model daily coal production at the most fundamental producing 
unit -the mine crew. The study shows that mine managers already have easy access to 
information that can help them explain, control, and predict production at the crew level. 
Computer-derived models were used to assess the relative effects of labor, technology, 
and environmental factors on the daily reported coal production of 81 mining crews at 7 
underground coal mines in the eastern U.S. coalfields. Almost all of the data came from 
daily production foreman reports, which are routinely gathered by most mining com- 
panies. 

Linear regression analyses were used to derive production models that accounted for 
a significant proportion of the day-to-day variation in coal production. This technique 
promises to become an inexpensive and useful management tool for detecting and 
diagnosing production problems, assessing the effectiveness of a change both before and 
after implementation, and isolating factors that lead to changes in production. Mine 
managers can readily implement this technique by using their daily crew reports and 
simple linear modeling software running on any available computer. 



INTRODUCTION 



All mines have a productivity problem. That is, no mat- 
ter how productive their operation is, mine managers often 
wonder if productivity is as high as it could be and, if not, 
how it can be improved. Part of the problem is informa- 
tion-there is a great deal of information available to 
managers about their mine's productivity, but this informa- 
tion is not in a form useful for timely decisionmaking. Thus, 
managing mine productivity is an ideal problem for the set 
of information management tools loosely categorized as 
decision support systems. This paper will describe a Bureau 
of Mines research project to develop and test a simple 
statistical decision support system for understanding and 
controlling the factors that can affect mine production. 

Statistical approaches to production management are 
neither new or unusual. However, the traditional statistical 
analyses used in mining usually approach the problem at a 
very distant, aggregate level of analysis. 2 



Research psychologist, Pittsburgh Research Center, Bureau of Mines, 
Pittsburgh, PA. 

2 Hill, F. E. Causes for the Productivity Decline in U.S. Coal Mining. Min. 
Congr. J., Sep. 1980, pp. 32-37. 

Suboleski, S. C, and C. B. Manula. Predicting the Effect of Physical Condi- 
tions on Productivity in Underground Coal Mines. Soc. Min. Eng. AIME 
preprint 80-44, 1980, 8 pp. 



While these tools are often useful for following gross 
fluctuations, they are too blunt and unresponsive to deal 
with some of the most important production processes, 
those that occur on a daily basis within individual mine sec- 
tions. An alternative method is to analyze events that occur 
daily and at the level of analysis of the individual mining 
crew. This is significant for several reasons. 

1. By focusing on the crew and section level of analysis in 
explaining factors that affect coal production, influences 
can be detected that would have been obscured in an ag- 
gregate analysis. 

2. Using systematic statistical modeling reveals the 
relative effects of different factors (e.g., labor, delays) on 
production. These effects would be difficult to detect in a 
less systematic "eyeball" perusal of the data. 

3. This method of systematic analysis is new to the mining 
industry and can make use of previously underexploited 
sources of information. Prior to this study, data were col- 
lected on production recordkeeping practices of a sample of 
26 coal mines. Although all of the studied mines maintained 
detailed daily production records from each section, none 
had a systematic method for using this information in their 
management decisionmaking. 



166 



The specific features of this approach that make it a 
unique and valuable method for understanding group per- 
formance include 

1. Using a single, concrete measure of performance: the 
number of tons of coal produced by each crew during each 
shift, 

2. Using the production function technique as the intellec- 
tual tool for selecting an initial set of variables. 

3. Relying on the cause and effect connections specified by 
the production function to predict how various factors will 
affect production prior to actually measuring the relation- 
ship. 

4. Recognition that when a mine section switches from 
one production method (e.g., advance room-and-pillar min- 
ing) to another (e.g., retreat mining with recovery of the 
pillars), the production process changes fundamentally and 
each method should be analyzed separately. 



The analytic strategy was derived from the production 
function, which is a basic management science technique for 
relating production inputs to production outputs. The 
dependent variable for coal mining output is tons of coal pro- 
duced. The independent variables can be described under 
the traditional categories of land, labor, and capital. Land, 
in the coal mining context, refers to physical condition 
variables such as seam height, quality of roof, quality of run- 
ways, and so on. The labor variable includes things such as 
the number of workers present and the quality of labor in 
terms of skills, abilities, and motivation. Capital, in this con- 
text, refers to the technology and technological policies, in- 
cluding the type and quality of mining equipment and the 
related mining policies that specify how and when equip- 
ment is to be used. 



METHODOLOGY 



SAMPLE 

Data in this report come from seven mines. Table 1 
describes the mines in terms of size and location. 



Table 1.— Description of mines 

Mine Employees Location 

1 180 Pennsylvania. 

2 394 Do. 

3 358 West Virginia. 

4 440 Virginia. 

5 207 West Virginia 

6 442 Illinois. 

7 444 Do. 



DATA BASE 

The data for this analysis are drawn primarily from pro- 
duction foremen reports. These are daily reports, filled out 
by the crew foreman, that include information on produc- 
tion, which crew members were present or absent, delay 
times and causes, physical conditions, and so forth. While 
each mine records information differently, all mines had in- 
formation about production, delays, and physical conditions. 
The specific form of the data or the level of differentiation 
of the data differed by mine. 



VARIABLES 

Table 2 describes the major variables used in the 
analysis. The variable name is given in the first column. Col- 
umns 2 and 3 provide the operational form and the source of 
the data. Note that because the raw data were taken from 
the mines' own records, some variables were only available 
for a subset of mines. The variables themselves can be 
grouped into five categories. 

The first category provides a measure of output (the 
dependent variable). This analysis primarily used total tons 
of coal mined by the crew during its shift as the principal 
measure. For mines 1 and 2, the variable was constructed 
from data on the number of shuttle cars loaded during the 
shift by the crew and the number of tons of coal associated 
with a loaded shuttle car in the various sections. For mine 3, 



the number of shuttle cars loaded was used as the depend- 
ent variable because of the lack of data about the conversion 
from loaded shuttle cars to tons of coal. In addition, the 
number of feet cut was tried as a dependent variable. 
However, the variability in seam height made this measure 
an even poorer measure of output than number of shuttle 
cars loaded. 

The second category of variables comprises several 
measures of the labor input. Crew size was used to assess 
the amount of labor available during the shift. Mines 1 and 2 
yielded even greater detail on this variable. They recorded 
crew sizes for both the prime crew and the general labor 
crew (hence the use of two crew size variables -prime crew 
size and general labor crew size). To account for idiosyn- 
cratic influences due to differences between crews, dummy 
variables for each crew were created. 

The third category of variables, and perhaps the most 
important single group in explaining production variation, 
was that of delays in production. Several measures of 
delays, distinguished for the most part by the equipment 
that caused the delays, were used. (See table 2 for the com- 
plete list of delay categories.) Because mine 3 reported 
delays in finer detail, it was possible to use more delay 
categories. In addition, bolter delays were entered as two 
variables (with the exception of mine 2) in order to 
distinguish differing effects on output of bolter delays that 
resulted in a cessation of mining activity (direct bolter delay) 
versus bolter delays that did not result in a cessation of min- 
ing (bolter delay). 

The fourth category was designed to account for the ef- 
fects of the mine's physical characteristics. Two types of 
variables were used. First was a measure of the physical 
quality of the section as reported by the foreman. The form 
of this report differed greatly from mine to mine, but it 
usually took the form of an index number such as = good 
and l = bad. Second was a dummy variable associated with 
each section, which was intended to account for the effect of 
general section differences on production. 

The last category contains several control variables. To 
account for the impact of an accident on production, the 
dummy variable accident was used to mark the shift and 
crew in which the accident occurred. Finally, to reveal in- 
fluences associated with working different shifts, the dum- 
my variables shift 2 and shift 3 were used. 



167 



Table 2.— Summary of variables used in analysis 



Variable name 



Operational form 



Source 



Output variables: 
Tons of coal produced 



Number of shuttle cars loaded. 

Number of feet cut 

Labor variables: 
Total crew size 



Prime crew size 

Number of general inside 

laborers. 
Dummy variable marking crew X. 
Equipment delay variables: 
Length of time continuous miner 

was not operational. 
Length of time shuttle cars were 

not operational. 
Length of time bolters were not 

operational but did not cause 

cessation of mining. 
Length of time bolters were not 

operational and caused 

cessation of mining. 
Length of time equipment was 

inside section other than miner, 

bolters, or shuttle cars. 
Length of time equipment outside 

section was not operational. 
Length of time other activities 

inside section occupied 

workers. 
Length of time managerial 

activities occupied workers. 1 
Length of time moving continuous 

miner within section. 

Number of shuttle cars 

Length of time loader was not 

operational. 
Length of time associated with 

stopping or starting. 
Length of delays caused by 

lack of empties. 

Physical conditions: 
Quality of physical conditions 

of the mine. 2 
Control variables: 

Dummy variable marking 

section X. 
Dummy variable marking 

accident. 
Dummy variable marking 

shift 2. 
Dummy variable marking shift 3. 



Tons of coal produced or loaded shuttle cars times conversion 
factor. 

Number of shuttle cars loaded during shift, including rock 
Depth, in feet, of cut into seam 



Number of all workers working as a unit at face (excluding 

supervisor). 
Number of workers running continuous miner, shuttle cars, and 

bolters. 
Number of workers (excluding supervisor) in crew not running 

continuous miner, shuttle cars, or bolters. 
1 if crew is X 

Sum of delays associated with equipment that is part of continuous 

miner. 
Sum of delays associated with equipment that is part of shuttle 

cars. 
Sum of delays associated with equipment that is part of bolters and 

not associated with a cessation of mining. 

Sum of delays associated with equipment that is part of bolters and 
was associated with a cessation of mining. 

Sum of delays associated with equipment other than miner, bolters, 
or shuttle cars. 



Sum of delays associated with equipment outside section 
Sum of delays associated with nonmining activities in section 

Sum of delays associated with managerial activities 



Sum of delays associated with moving continuous miner within 
section. 

Number of shuttle cars available for at least half the shift 

Sum of delays associated with loader 



Sum of times associated with preparing to stop or start 
Sum of times associated with lack of empties 



0-1 (good or bad), mines 1-5; 1-4 (good to bad), mine 2; 1-5 (good to 
bad), mine 4; delay in minutes, mine 3. 

1 If section is X 

1 if an accident occurred during reported interval 

1 if data are from 2d shift 

1 if data are from 3d shift 



Company records or created by 
analysts based on company 
records. 

Company records. 
Do. 

Do. 

Created by analysts based on 
company records. 
Do. 

Do. 

Do. 

Do. 

Do. 



Do. 

Do. 

Do. 
Do. 

Do. 

Do. 

Do. 
Do. 

Do. 

Company records or created by 
analysts based on company 
records. 

Created by analysts based on 
company records. 

Do. 

Do. 

Do. 

Do. 



'Includes scheduled lunch breaks, trips to and from face, and inspections. 

2 For mine 4, quality of physical conditions was actually 2 variables— bottom conditions and top conditions. 



BASELINE MODEL 



The basic model to be estimated was 



The baseline model represents the basic production 
function for an underground coal mining crew. It expresses 
the dependent variable (tons of coal) as a linear function of 
all the independent variables discussed previously. The pur- 
pose of this model is to estimate the relative importance of 
those input factors that directly affect production. The 
baseline model is basic in the sense that it incorporates 
several simplifying assumptions, specifically that the func- 
tion is linear in form and that the same computed model is 
valid for all the sampled crews at a mine. The validity of 
these assumptions can be tested by comparing the baseline 
model with more complex models that do not make the 
simplifying assumptions. 

The analytic strategy, then, was to begin with a basic 
production function. After the model was tested against the 
hypotheses, the next stage was to examine whether more 
complicated versions of the model provide better ex- 
planatory power. The additional analyses revealed no 
significant nonlinearities or crew-to-crew fluctuations and 
are therefore not reported here. 



Tons of coal = crew size + miner delay + bolter delay + 
direct bolter delay + shuttle car delay + inside equipment 
delay + outside equipment delay + other activity delay + 
managerial delay + number of shuttle cars + physical con- 
ditions + shift 2 dummy + shift 3 dummy + accidents. 

The exact set of variables used, of course, varied from the 
preceding list according to their availability from mine to 
mine. 

Table 3 presents the expected signs of the coefficients. 
The labor variable should have a positive effect on produc- 
tion. All the delay variables should have negative signs. 
Number of cars, an equipment variable, is positively 
related - having less than the regular two cars usually 
degrades a crew's production. The physical condition 
variable has a negative sign, which reflects the coding of 
that variable (0 = good conditions, 1 = bad conditions). 

It is difficult to judge the effects of shifts, hence the 
positive and negative signs attached to these variables. 



168 



However, the existence of an accident is disruptive and 
should reduce production, hence the negative sign. 

For some variables, it is possible to only hypothesize the 
relative magnitudes of the coefficients. For example, delays 
in the continuous minor stop the production of coal, while 
delays in one of the cars only slow the production of coal. So 
the effect of continuous miner delay should be greater than 
the effect of car delays. Similarly, direct bolter delay, which 
stops the continuous miner from advancing, has a greater 
impact than indirect bolter delay, which means the bolter is 
down but the miner is still producing. 



Table 3.— Expected impact of independent variables on output 



Expected 
Variable effect 

Crew size + 

Miner delay - 

Bolter delay 

Direct bolter delay . . - 
Shuttle car delay .... 
Inside equipment 

delay - 

Outside equipment 

delay 



Expected 

Variable effect 

Other activity delay . . 

Managerial delay .... - 

Number shuttle cars . + 
Physical conditions . . 

Accident - 

Shift 2 dummy ± 

Shift 3 dummy ± 



RESULTS 



Table 4 presents the estimated models for mines 1 
through 7. For each mine, table 4 shows the explained 
variance (R 2 ) and the regression coefficients for the input 
variables, the R 2 or percentages of explained variance for 
the majority of the mines are fairly comparable, ranging 
from 0.46 to 0.63. This indicates that the models' ex- 
planatory powers for the mines are similar, accounting for 
roughly half of the variation found in the dependent 
variable, output. The only exception is mine 3, where the 
dependent variable is different from that of the other 
models. This finding of a common R 2 across most of these 
mines is important. Consider the simple fact that the pro- 
cedure for recording data and measuring variables differs 
across these mines. Yet when the model is computed across 
mines, there is a reasonable and similar fit for each mine. 
The form of the model is also similar for each mine: the 
signs of the coefficients and the magnitudes are in the 
predicted direction for most of the variables in most of the 
mines. 



Subsequent analysis revealed additional commonalities 
across the baseline models. In cases where data were 
available, different models were generated from pillaring 
versus developmental miming crews, as was expected. Also, 
the introduction of the section variable, a surrogate for 
machinery and physical condition differences, makes a 
significant contribution to explaining variation in output. 
The introduction of the crew variable also makes a dif- 
ference. When the section and crew variables are intro- 
duced together, the crew differences are important in three 
of the five mines where data were available. 

These observations about similarities are important 
because they deal with the primary objective of this 
paper -to estimate models of crew productivity. The key 
finding is that one can estimate this model of crew produc- 
tivity across very different mines and identify models that 
exhibit similar explanatory power. Further evidence for the 
robustness of this technique lies in the close correspondence 
between the hypothesized model and the observed relation- 
ships between real-life conditions and outputs. 



Table 4.— Summary of baseline runs for all mines showing model coefficients 

Mine 1 Mine 2 Mine 3 Mine 4 Mine 5 

N 3,659 2,565 1,162 1,289 2,327 

R ! 0.54 0.63 0.29 0.53 0.50 

Dependent variable (') ( 1 ) ( 2 ) (') (') 

Independent variable: 

Total crew size NAp NAp 0.87 0.96 8.6 

Prime crew 6.3 2.6 NAp NAp NAp 

Number of general inside laborers 5.9 1.7 NAp NAp NAp 

Shift 2 dummy 2.3 -0.71 2.4 NAp NAp 

Shift 3 dummy 4.8 1.2 3.2 -38.2 -2.8 

Miner delay -0.43 -0.25 -0.06 -0.58 -0.82 

Shuttle car delay -0.10 -0.05 -0.01 -0.12 -0.15 

Bolter delay -0.03 -0.05 -0.03 -0.32 -0.25 

Direct bolter delay -0.50 NAp -0.02 -0.62 -0.70 

Inside equipment delay -0.36 -0.23 -0.04 -0.63 -0.63 

Outside equipment delay -0.37 -0.26 -0.03 -0.35 -0.75 

Other activity delay -0.42 -0.20 0.01 -0.60 -0.79 

Managerial delay -0.55 -0.23 -0.04 -0.62 -0.97 

Miner move delay -0.36 -0.26 -0.01 -0.25 -0.82 

Hours worked NAp NAp NAp NAp NAp 

Load delay NAp NAp - 0.01 NAp NAp 

Delay in preparing to stop or start NAp NAp -0.01 NAp NAp 

Empty delay NAp NAp - 0.03 NAp NAp 

Wreck delay NAp NAp -0.06 NAp NAp 

Physical conditions -15.5 -26.2 -0.05 3 -0.78 -35.5 

' -4.5 

Accident -7.3 -7.4 NAp 20.6 -17.5 

Number of shuttle cars 31.8 18.2 2.1 32.1 36.5 

Constant 112.6 172.6 13^3 266.4 363.5 

NAp Not applicable. 3 Physical condition of bottom. 

'Tons of coal produced. 'Physical condition of top. 

'Number of shuttle cars loaded. 



Mine 6 



Mine 7 



2,170 


1,829 


0.46 
(') 


0.49 
(') 


NAp 


NAp 


17.5 


-12.3 


17.9 


1.3 


12.5 


-8.8 


16.5 


15.5 


-1.7 


-1.8 


-0.67 


-0.62 


-2.2 


-1.1 


-0.29 


0.91 


-1.3 


-1.2 


-0.68 


-0.38 


-0.58 


-0.40 


-2.2 


-2.2 


-2.7 


-1.8 


82.8 


62.7 


NAp 


NAp 


NAp 


NAp 


NAp 


NAp 


NAp 


NAp 


NAp 


NAp 


NAp 


NAp 


NAp 


NAp 


99.7 


270.6 



169 



DISCUSSION 



The purpose of this study was to develop a model of coal 
production at the crew level. While most of the research in 
this area has focused on explaining productivity changes at 
the industry level, the results from this study indicate that it 
is also valuable to focus on the basic production unit -the 
crew. Furthermore, the results show that one can estimate 
a general production function across a varied set of mines. 
While it is difficult to draw refined distinctions across the 
mines because of differences in data sets and operational 
procedures, the analysis has revealed a fairly robust model. 
The explanatory power of the model is respectable and 
similar across these different mining settings. Also, the 
hypothesized form of the model, originally specified in table 
3, appears to be confirmed. That is, the hypothesized signs 
and magnitudes of the production function are consistent 
with the estimated models. Thus, similar results could be 
confidently expected if the model is transferred to other 
mining settings. 

This technique complements the usual aggregate or 
"macro" approach. It also offers an alternative to conven- 
tional "micro" approaches to group effectiveness re- 
search-particularly traditional social-psychological 
theories. Variables such as cohesiveness and group interac- 



tion are the typical foci of group effectiveness studies. A 
review of that literature 3 indicates that the evidence show- 
ing the impact of these variables on productivity is 
equivocal, at best. Therefore, this paper proposes the pro- 
duction function model as an alternative approach. If the 
analyst still suspects social-psychological variables to be im- 
portant, the crew variable can be added to the model as a 
convenient crew level surrogate for these variables. 

While the explanatory power of the models appears 
stronger than that of other organizational studies of work 
groups, there were still portions of the variation in coal pro- 
duction that remained unexplained. Analyses of the regres- 
sion residuals and possible reporting bias by the foremen 
were undertaken to explore possible additional sources of 
explainable variance. In addition, many other analyses, at a 
mine level, were performed to sort out issues in coding and 
representing data. These analyses did not substantially in- 
crease the explanatory power of the models and are not 
reported here. Also, the cost of doing these additional 
analyses is substantial, and additional investments of 
analytic time are prohibitively expensive relative to the in- 
creased ability to explain variations in production. 



USING PRODUCTION MODELS AS A MANAGERIAL TOOL 



The development of within-firm production models can 
be a very effective tool for improving productivity at the 
mine level. An informal examination of a larger sample of 
26 mines and 17 companies revealed nothing resembling the 
proposed production modeling method, but many of the 
companies could have beneficially implemented this tech- 
nique at minimal cost. 

Most of the mines in the sample, but not all, keep daily 
production data. These data, generated at the crew level are 
typically aggregated to the section level. The most common 
types of data are tons produced, tons produced per number 
of miners, and the delay variables. These data are reviewed 
by the superintendent each day, with the most attention 
paid to tons produced. Some mines computer-tabulate this 
information so it is available on a weekly, monthly, or yearly 
basis, whereas some mines do nothing with the data. These 
production reports also typically limit their focus to tons per 
mining unit or tons per number of miners per unit. None of 
the companies studied issue reports that link the input 
(delays) and output (production). The delay variables are 
often recorded and sent to the head of maintenance without 
any mention of corresponding losses or gains in production. 
Matching the data on inputs and outputs is essential for us- 
ing these data for effective decisionmaking. 

Consider the following scenario: You are a mine 
manager and have before you daily or weekly data on pro- 
duction of coal in the typical report format. Assume that the 
data are at the section level. You observe that sections A 
and B produce the same amount of coal. You may well 
wonder whether they are equivalent producing sections and 
whether you can expect them to both produce the same 
amount tomorrow, next month, or next year. You cannot 
know for certain because of the failure to relate inputs to 
outputs. For example, if section A had poor physical condi- 
tions and produced as much as B, we could say A is more 



productive. If A were pillaring and B doing developmental 
mining, we would say A is less productive. If we say A is 
pillaring and working under poor conditions, A's relative 
productivity is harder to judge because pillaring and 
physical conditions have opposite effects on production. 

The point is that there are a large number of variables 
(shift, delays, accidents) that affect production, and these in- 
puts have a complicated set of effects on output. This paper 
asserts that solely looking at output without any formal 
model reduces the utility of production information as a 
valuable managerial resource. Or, to put it another way, the 
use of production models can prove to be a valuable 
managerial tool and an improvement over the current pro- 
cedures for using production information. 

There are two major ways in which the model procedure 
in this paper can be used as an effective managerial tool: as 
a diagnostic tool and as a tool for assessing change. 



A DIAGNOSTIC TOOL 

The production model introduced in this paper can be a 
new analytic tool for managers. It can serve as a powerful 
way to detect increases or decreases in coal production by 
crew or section. The way to do this follows. Think of any of 
the baseline models presented in table 4. These models 
represent the average production function for the crews at a 
mine. The models can be thought of as a set of weights for 
input variables that affect production. The use of the term 
"baseline model" implies that, given the type of technology 
and labor at a given time, this model is fairly stable and 



3 Goodman, P. S., E. C. Ravlin, and L. Argote. Current Thinking About 
Groups: Setting the Stage for New Ideas. Ch. in Designing Effective Work 
Groups, ed. by P. S. Goodman. Jossev-Rp^ i° oc m i""-ifi7 



170 



representative of the production process in any crew at this 
mine. In a sense, this model is a standard by which future 
production can be judged. 

A useful strategy, then, is to use this modeling pro- 
cedure to evaluate future production. That is, for any time 
period a manger can enter the values of the input variables 
and multiply these by the coefficients. Using mine 1 as an 
example, if the manager wanted to assess production on a 
particular day, he or she would determine the delay times 
per machine and multiply these by the coefficients. So if 
there were 100 min in miner delay, the manager could use 
the model to predict a loss of 43 st (100 x 0.43 = 43). To 
assess total predicted production, all of the products and the 
constant are added together. The predicted number of tons 
could then be compared against the actual amount pro- 
duced. 

If predicted production is found to be lower than actual 
production, that particular crew would have been more pro- 
ductive than expected. Similarly, if predicted production ex- 
ceeds actual production, productivity would be lower than 
expected. Again, since the production model reflects inputs 
and output, the results of this analysis are much more inter- 
pretable than looking simply at output. 

The preceding example uses the production model as a 
tool for analyzing variations in production. In that sense it is 
a diagnostic tool because it can tell if production is higher, 
the same, or lower than expected. Managers may want to 
use the model to establish a range of acceptable production 
for each section at their mines. If crew performance drops 
below the minimum value of the range, then remedial action 
may be necessary. Likewise, if a crew exceeds the top value 
of the range, special rewards may be in order. 

There are other diagnostic uses of production modeling. 
For example, one can systematically assess the effect of ac- 
cidents on production. The effects of absenteeism can also 
be evaluated. If it is assumed that variation in the labor 
variable is primarily affected by absenteeism, a logical ques- 
tion would be what would happen to production if 
absenteeism were reduced. This would be answered, for ex- 
ample, by changing the labor variable to reflect better atten- 
dance and then asking the model to show the predicted in- 
crease in production. The additional production represents 
the cost of the existing level of absenteeism. 



A TOOL FOR ASSESSING CHANGE 

Managers often introduce new programs to improve 
production. These programs might vary from a new train- 
ing program to a new maintenance system. They assume 
that these changes will modify the production function of 
the mine. Simply looking at output changes before and after 



the intervention will not be informative for the reasons sug- 
gested previously in this paper. For instance, if a new train- 
ing program was introduced and production increased by 5 
pet after the training program began, simply looking at 
these output data might invite one to infer that the training 
program increased production. 

However, it is known from this paper that multiple fac- 
tors (e.g., physical conditions) can increase production and 
these factors are unrelated to the training. So, without con- 
trolling for these potentially confounding variables, it is dif- 
ficult to know how to explain the 5-pct increase in produc- 
tion. Production modeling is ideally suited for this analysis 
because it statistically controls for the multiple variables 
that affect productivity. That is, it allows the manager to 
isolate the different factors (e.g., training and physical con- 
ditions) that affect the production of coal. 

The following example shows how production modeling 
can be used to evaluate a managerial change. Assume that a 
mine manager has introduced a program for improving min- 
ing practices. The decisionmaker should analyze historical 
data to estimate a baseline model prior to making any 
changes and assume that an effective training program will 
improve productivity. These changes should be reflected in 
the production model, either in the constant or in coeffi- 
cients. One simple test is to reestimate the model before and 
after the change and introduce a dummy variable for the 
period change. A significantly large coefficient for the dum- 
my variable will provide some evidence on the effectiveness 
of the changes. 

A more sophisticated method is to follow the initial 
baseline estimate with the introduction of daily input 
variables into the production model to determine predicted 
production for the change period. If the training has shifted 
the production model, the actual production for the change 
period should exceed the predicted production. A 
demonstration of this procedure was shown by Goodman. 4 

Given the increased utilization of computers in the min- 
ing industry and the availability of software, the task of con- 
structing these production models is feasible. Most mines 
are already collecting the necessary data. Rather than con- 
tinuing to fill out the conventional handwritten report, they 
could directly enter the data into a computer. In any case, 
the data can be easily input and fairly easily processed with 
existing software. The number of microcomputer software 
packages that include linear modeling functions is growing 
constantly. Most of these programs can be used to do the 
relatively basic analysis described in this paper, and many 
can analyze even more sophisticated models. 



4 Goodman, P. S. (ed.). Assessing Organizational Change. Wiley, 1979, 391 



pp. 



*U. S. GOVERNMENT PRINTING OFFICE 1987: 189-320/70087 



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